Self-repairing microcapsule, phosphate coating and preparation method of self-repairing microcapsule and phosphate coating

Abstract

The invention relates to a self-repairing microcapsule which is characterized by being prepared by the following steps: (1) stirring and mixing melamine, formaldehyde and deionized water, and carrying out addition reaction under an alkaline condition to form a water-soluble transparent prepolymer A; (2) dissolving diethyl aluminum hypophosphite and lauryl sodium sulfate in deionized water, adding organosilane and toluene, emulsifying to form a stable emulsion B, slowly pushing the emulsion B into the prepolymer A to obtain a polymerization solution, and completing polycondensation coating; and washing to remove the excessive prepolymer A, and drying to obtain the self-repairing microcapsule. The self-repairing microcapsule synthesized in the invention is biodegradable, green and environment-friendly, conforms to the current thought of green development, and can also be used as a repairing agent for other porous materials. According to the inorganic phosphate coating disclosed by the invention, the self-repairing microcapsules and the passivated aluminum particles are added into the phosphate coating, so that an effect of physically resisting a corrosive medium can be achieved.

Description

TECHNICAL FIELD

[0001] The present application relates to a microcapsule material which can be applied in a coating, and to a wear-resistant and corrosion-resistant phosphate coating, and to a method for preparing the phosphate coating. BACKGROUND

[0002] The rapid development of aerospace, ocean engineering, rail transportation, high-tech energy and other fields has put forward higher requirements for the protection of metal surfaces. Corrosion and wear often cause irreversible damage to metals, resulting in significant economic losses. Among various protection measures, coating technology is the most effective, economical and widely used. Coatings are mainly divided into organic coatings and inorganic coatings. Among them, organic coatings (such as epoxy resin, polyurethane, etc.) have high penetration and excellent corrosion resistance, etc., and have been proven to effectively protect metals in marine environments. However, environmental pollution, high toxicity and easy aging are the main shortcomings of organic coatings. In particular, poor high-temperature resistance greatly limits the application range of organic coatings. On the contrary, inorganic coatings play an indispensable role in the protection of metal surfaces due to their wide temperature range, stable chemical properties, and environmental protection. The main types of inorganic coatings commonly used at present are silicates, phosphates and borates, among which phosphate coatings are a kind of inorganic coating with simple preparation process, low cost and environmental friendliness. However, due to the porous structure of phosphate coatings, there are still some defects, such as high brittleness, poor corrosion resistance, poor wear resistance, etc. Enhancing the wear resistance and corrosion resistance of phosphate coatings in harsh environments is still a challenge.

[0003] Introducing organic materials into inorganic materials is also one of the effective methods to increase wear resistance and corrosion resistance. The patent document can refer to the Chinese invention patent application publication “Preparation method of high cohesive force and adhesion organic-inorganic composite phosphate coating” (application publication number CN117659753A) with application number 202311705349.0. The document combines chromium magnesium phosphate solution with low degree of polymerization hydroxy polysiloxane, combines spherical aluminum powder and nano silicon dioxide, and forms a high cohesive force and adhesion organic-inorganic composite phosphate coating. The problem of insufficient strength of existing coating materials on high-speed rotating parts is solved, and high-performance solidification of the coating is achieved.

[0004] Reference can also be made to Chinese Invention Patent No. ZL202211185726.8, entitled "Preparation method of organic-inorganic composite phosphate", (authorized publication number CN115678314B), which prepares organic-inorganic composite phosphate by in-situ method. The organic-inorganic composite phosphate is prepared by preparing an organic silica sol pre-polymer solution with phosphoric acid and acetic acid and an ammonium carbonate-ammonia prepared phosphate precursor solution. The organic silica sol pre-polymer solution is added to form an organic-inorganic composite phosphate, which solves the problems of poor stability and dispersibility of phosphate pigments in coatings, improves the protective performance of the coating, and realizes environmental protection and economy of the process. Through the combination of organic and inorganic elements, the coating can effectively utilize the unique qualities of the organic and inorganic phases and combine their advantages. However, the organic or inorganic elements in the material prepared by blending are prone to aggregation, which is not conducive to the homogenization of the coating. SUMMARY

[0005] The first technical problem to be solved by the present application is to provide a self-repairing microcapsule for use in phosphate coating to improve the corrosion resistance and comprehensive mechanical properties of the coating.

[0006] The second technical problem to be solved by the present application is to provide a phosphate coating with high corrosion resistance and comprehensive mechanical properties.

[0007] The third technical problem to be solved by the present application is to provide a preparation method of a phosphate coating with high corrosion resistance and comprehensive mechanical properties.

[0008] The technical solution adopted by the present application to solve the first technical problem is as follows:

[0009] ①Stir and mix 5-7 parts of melamine, 9-12 parts of formaldehyde and 25-35 parts of deionized water. When all the melamine is dissolved, add triethanolamine to the solution to reduce the pH to 8-10 to obtain a mixed solution. Heat and stir the mixed solution in an oil bath. The addition reaction under alkaline conditions forms a water-soluble transparent pre-polymer A;

[0010] ②Dissolve 0.5-2 parts of aluminum diethylphosphinate and 0.5-2 parts of sodium dodecyl sulfate in 100-120 parts of deionized water. Add 5-10 parts of organosilane and 8-14 parts of toluene. Stir at room temperature for 15-25 minutes to form a stable emulsion B. Place pre-polymer A and emulsion B in separate phase containers. Slowly push emulsion B into pre-polymer A at a certain air pressure to obtain a polymerization solution. Adjust the pH of the polymerization solution to acidity with acetic acid. React the polymerization solution at 65-75°C for 1-5 hours to complete the condensation coating. After washing, remove the excess pre-polymer A. Dry to obtain self-repairing microcapsules.

[0011] The above-mentioned parts are all by weight.

[0012] Preferably, the heating temperature of the addition reaction in step 1 is 65-75℃, and the stirring time is 1-2h.

[0013] Preferably, the silane in step 2 is at least one of fluorooctylethyltriethoxysilane, heptadecafluorodecyltriethoxysilane, perfluorohexylethyltriethoxysilane and perfluorodecyltrimethoxysilane.

[0014] Preferably, the air pressure used for slowly pushing the emulsion B into the prepolymer A in step 2 is 10-15kPa.

[0015] Preferably, the rotating speed of the emulsification in step 2 is 2000-4000r / min.

[0016] Preferably, the pH of the polymerization solution in step 2 is adjusted to 5-6 by acetic acid.

[0017] Preferably, the drying condition in step 2 is as follows: drying at 60-100℃ in a drying oven for 36-48h.

[0018] The technical solution adopted by the present application to solve the second technical problem is: a phosphate coating with self-repairing microcapsules, characterized by comprising the following components and their weight ratios:

[0019] Phosphate aqueous solution 80-120 parts;

[0020]

[0021] The mass fraction of the phosphate in the aforementioned phosphate aqueous solution is 50-70%.

[0022] Preferably, the passivated aluminum particles are prepared by the following steps:

[0023] The aluminum particles are dispersed into a zirconium-based passivation solution, and after ultrasonic treatment for 1-5min, the passivated aluminum particles are collected by filtration and repeatedly washed with deionized water.

[0024] Preferably, the zirconium-based passivation solution is composed of the following components and their concentrations: zirconium sulfate 0.1-0.2g / L, sodium tripolyphosphate 0.1-0.2g / L, organic acid 0.8-1.5g / L, and the pH of the zirconium-based passivation solution is 3.5-4.2.

[0025] Preferably, the aluminum particles are nano aluminum particles with a diameter of 10-50nm.

[0026] Preferably, the phosphate is at least one of aluminum phosphate AlPO4, aluminum dihydrogen phosphate Al(H2PO4)3, and aluminum hypophosphite Al(PO2H2)3.

[0027] Preferably, the inorganic curing agent is at least one of iron oxide Fe2O3, magnesium oxide MgO, aluminum oxide Al2O3, and zinc oxide ZnO.

[0028] The technical solution adopted by the present application to solve the third technical problem is a preparation method of a phosphate coating, characterized by comprising the following steps:

[0029] The phosphate aqueous solution and the inorganic curing agent are mixed, deionized water is added, passivated aluminum particles and self-repairing microcapsules are added, and magnetic stirring is performed at room temperature for 1-2 hours to obtain a self-repairing phosphate coating slurry;

[0030] The substrate glass is degreased by ethanol ultrasonic for 20-40 minutes, washed with pure water, and dried by nitrogen blowing; air spraying is adopted to spray the coating onto the glass substrate, and gradient temperature curing is performed to obtain the phosphate coating.

[0031] Preferably, the air spraying pressure is 0.3-0.5 MPa.

[0032] Preferably, the gradient curing temperature has three stages, which are 40-60℃, 100-120℃, and 180-200℃, respectively, and the curing time of each temperature stage is 20-30, 50-60, and 80-90 minutes, respectively.

[0033] Compared with the prior art, the present application has the advantages that functional microcapsules are embedded in the multi-dimensional network structure of the phosphate matrix. This technical solution improves the protective performance of the coating through a double-acting mechanism: first, the microcapsules fill the internal pores and microcracks of the coating, significantly improving the coating density and constructing a physical barrier to delay the penetration of corrosive media; second, the microcapsules and micron-sized aluminum oxide particles cooperatively construct a micro-nano composite structure, which simultaneously improves the hardness, cohesive strength, and impermeability of the coating through interface strengthening effect. When the coating is subjected to long-term immersion or mechanical damage, the microcapsule shell ruptures to release the internal repair agent, which undergoes hydrolysis reaction to generate active silanol groups when it comes into contact with water, and forms a three-dimensional network repair film layer through self-crosslinking reaction. This film layer has both physical barrier and chemical protection functions: on the one hand, it effectively isolates the corrosive medium as a dense barrier, and on the other hand, it improves the corrosion resistance of the metal matrix through silicon-oxygen chemical bonding, and reduces the permeability of the coating to water by introducing groups with excellent hydrophobicity. The addition of passivated aluminum particles in the coating can improve the corrosion resistance and comprehensive mechanical properties of the coating.

[0034] Specifically, the present application adds aluminum particles passivated in a zirconium solution in the phosphate coating, reduces the adsorption energy of corrosive media such as chloride ions Cl-, and improves the corrosion resistance of the coating in extreme environments.2. The self-repairing melamine urea resin microcapsules added in the present application make the phosphate coating have self-healing function, and the self-repairing capsules hydrolyze and polymerize when in contact with electrolytes, forming a new protective film and prolonging the service life of the coating.3. The self-repairing microcapsules in the present application can form a lubricating film at the wear site, reducing the brittleness of the phosphate coating and improving its comprehensive mechanical properties.

[0035] The inorganic phosphate coating with self-repairing properties of the present application adds self-repairing microcapsules and passivated aluminum particles in the phosphate coating, which can physically resist corrosive media. When the coating cracks, the microcapsules are impacted by the corrosive medium, releasing the internal repair liquid, thereby achieving self-repairing effect, realizing the service life and corrosion resistance of the phosphate coating.

[0036] Therefore, the implementation of implanting nanoparticles and organic materials in the phosphate coating and in-situ and controlled transient release of organic materials can effectively solve the defects of high brittleness and poor crack resistance of the phosphate coating, and at the same time improve the dispersibility of organic materials in inorganic phosphate, which is crucial for enhancing the wear resistance and corrosion resistance of the phosphate coating. BRIEF DESCRIPTION OF DRAWINGS

[0037] Figure 1 The hardness chart of the coating sample of each example and comparative example.

[0038] Figure 2 The water absorption rate change chart of the coating sample of each example and comparative example immersed in 3.5wt.% solution. DETAILED DESCRIPTION

[0039] The present application is further described in detail below in combination with examples and drawings.

[0040] Example 1

[0041] First, prepare self-repairing melamine urea resin microcapsules:

[0042] Stir and mix 5 parts of melamine, 9 parts of formaldehyde and 25 parts of deionized water. Once all the melamine is dissolved, add triethanolamine to the solution to reduce the pH to about 8. Subsequently, heat the solution to 65 °C in an oil bath, stirring for 1 h, this step is mainly the addition reaction of melamine and formaldehyde under alkaline conditions to form a water-soluble transparent prepolymer A. Dissolve 2 parts of aluminum diethylphosphinate and 2 parts of sodium dodecyl sulfate in 120 parts of deionized water, add 10 parts of fluorooctyl ethyl triethoxysilane and heptadecafluorodecyl triethoxysilane and 14 parts of toluene solution, stir at room temperature for 25 minutes, and emulsify at a high speed of 2000 r / min to form a stable emulsion B. Prepolymer A and emulsion B are placed in the dispersed phase container and the continuous phase container, and emulsion B is slowly pushed into prepolymer A under a gas pressure of 10 kPa, and the stirring speed of prepolymer A is 600 r / min. Subsequently, the solution is adjusted to pH 5 with acetic acid, and the solution is reacted at 65 °C for 1 hour to complete the condensation coating. Finally, the polymerization solution is washed with ethanol and deionized water several times to remove excess prepolymer A by centrifugation, and dried in a drying oven at 60 °C for 36 hours to obtain self-repairing microcapsules.

[0043] Second step, preparation of phosphate coating:

[0044] Aluminum particles with a diameter of 10 nm are dispersed into a zirconium-based passivation solution with components of zirconium sulfate (0.1 g / L), sodium tripolyphosphate (0.1 g / L), and organic acid (0.8 g / L), and the solution pH is 3.5. After 1 minute of ultrasonic treatment, the passivated aluminum particles are collected by repeated washing with deionized water and filtration. Mix 80 parts of a 50% mass fraction aluminum dihydrogen phosphate Al(H2PO4)3 aqueous solution with 10 parts of an inorganic curing agent Al2O3, add 80 parts of deionized water, and add 10 parts of passivated aluminum particles. Stir magnetically at room temperature for 1 hour to obtain a self-repairing phosphate coating stock solution. Degrease the glass substrate with ethanol for 20 minutes under ultrasonic treatment, wash with pure water for 2 times, and dry with nitrogen. Spray the coating onto the glass substrate using air spraying at 0.3 MPa, and perform gradient temperature curing in three times with temperatures and times of 40 °C, 20 minutes, 100 °C, 50 minutes, and 180 °C, 80 minutes, respectively.

[0045] Example 2

[0046] First step, preparation of self-repairing melamine urea-formaldehyde resin microcapsules:

[0047] The 7 parts of melamine, 12 parts of formaldehyde and 35 parts of deionized water were stirred and mixed. Once all the melamine was dissolved, triethanolamine was added to the solution to reduce the pH to 9. Subsequently, the solution was heated in an oil bath with stirring for 1.5 h, which was mainly the addition reaction of melamine and formaldehyde under alkaline conditions to form a water-soluble transparent prepolymer A. 1 part of aluminum diethylphosphinate and 1 part of sodium dodecyl sulfate were dissolved in 110 parts of deionized water, 7 parts of heptadecafluorodecyl triethoxysilane and perfluorohexyl ethyl triethoxysilane were added, and 10 parts of toluene solution was added, stirred at room temperature for 20 minutes, and emulsified to form a stable emulsion B by high-speed stirring at 3000 r / min. The prepolymer A and the emulsion B were placed in the dispersed phase container and the continuous phase container, and the emulsion B was slowly pushed into the prepolymer A under the air pressure of 12 kPa, and the stirring speed of the prepolymer A was 800 r / min. After the emulsion B was completely pushed into the prepolymer A, the solution was then adjusted to pH 6 with acetic acid, and the solution was reacted at 70°C for 3 hours to complete the condensation coating. Finally, the polymerization solution was washed several times with ethanol and deionized water to remove excess prepolymer A by centrifugation, and dried in a drying oven at 80°C for 42 hours to obtain self-repairing microcapsules.

[0048] Second step, preparation of phosphate coating:

[0049] The aluminum particles, 30 nm in diameter, were dispersed into a zirconium-based passivation solution with components of zirconium sulfate (0.15 g / L), sodium tripolyphosphate (0.15 g / L), and organic acid (1.0 g / L), and the solution pH was 4.0. After 3 minutes of ultrasonic treatment, the passivated aluminum particles were collected by repeated washing with deionized water and filtration. 100 parts of an aqueous solution of aluminum phosphate AlPO4 and aluminum dihydrogen phosphate Al(H2PO4)3 with a mass fraction of 60% and 15 parts of magnesium oxide MgO were mixed, 100 parts of deionized water were added, 15 parts of passivated aluminum particles were added, 6 parts of self-repairing microcapsules were added, and magnetic stirring was performed at room temperature for 1.5 hours to obtain a self-repairing phosphate coating stock solution. The substrate glass was degreased by ultrasonic treatment in ethanol for 30 minutes, washed with pure water for 3 times, and dried with nitrogen. The coating was sprayed onto the glass substrate using air spraying at 0.4 MPa, and gradient temperature curing was performed in three times. 50°C, 25 minutes, 110°C, 55 minutes, 190°C, 85 minutes.

[0050] Example 3

[0051] First step, preparation of self-repairing melamine urea-formaldehyde resin microcapsules:

[0052] Stir and mix 6 parts of melamine, 10 parts of formaldehyde and 30 parts of deionized water. Once all the melamine is dissolved, add triethanolamine to the solution to reduce the pH to about 10. Subsequently, heat the solution to 70°C in an oil bath, stirring for 1.5 h, which is mainly the addition reaction of melamine and formaldehyde under alkaline conditions to form a water-soluble transparent prepolymer A. Dissolve 0.5 parts of aluminum diethylphosphinate and 0.5 parts of sodium dodecyl sulfate in 120 parts of deionized water, add 10 parts of a solution of heptadecafluorodecyltriethoxysilane, perfluorohexylethyltriethoxysilane and perfluorodecyltrimethoxysilane in toluene, stir at room temperature for 15 minutes, emulsify to form a stable emulsion B at a high speed of 4000 r / min. Put the prepolymer A and the emulsion B into the dispersed phase container and the continuous phase container, slowly push the emulsion B into the prepolymer A at a gas pressure of 15 kPa, and the stirring speed of the prepolymer A is 900 r / min. After the emulsion B is completely pushed into the prepolymer A, subsequently, adjust the solution to pH 5 with acetic acid, and react the solution at 75°C for 5 hours to complete the condensation coating. Finally, wash the polymerization solution with ethanol and deionized water several times to remove excess prepolymer A by centrifugation, and dry in a drying oven at 100°C for 48 hours to obtain self-repairing microcapsules.

[0053] Second step, preparation of phosphate coating:

[0054] Disperse aluminum particles with a diameter of 50 nm into a zirconium-based passivation solution with components of zirconium sulfate (0.2 g / L), sodium tripolyphosphate (0.2 g / L), and organic acid (2.0 g / L), solution pH 4, ultrasonic treatment for 5 minutes, repeatedly rinse with deionized water, and collect the passivated aluminum particles by filtration. Take 120 parts of a 70% mass fraction aqueous solution of aluminum phosphate AlPO4, aluminum dihydrogen phosphate Al(H2PO4)3, and aluminum hypophosphite Al(PO2H2)3, and mix with 20 parts of inorganic curing agent alumina Al2O3 and zinc oxide ZnO, add 120 parts of deionized water, add 20 parts of passivated aluminum particles, 9 parts of self-repairing microcapsules, and magnetically stir at room temperature for 2 hours to obtain a self-repairing phosphate coating stock solution. Degrease the glass substrate with ethanol for 40 minutes by ultrasonic, wash with pure water for 4 times, and dry with nitrogen. Spray the coating onto the glass substrate using 0.5 Mpa air spraying, and perform gradient temperature curing in three times. 60°C, 30 minutes, 200°C, 60 minutes, 200°C, 90 minutes.

[0055] Comparative Example 1 without passivated aluminum particles

[0056] First step, preparation of self-repairing melamine urea-formaldehyde resin microcapsules:

[0057] The 5 parts of melamine, 8 parts of formaldehyde and 25 parts of deionized water were stirred and mixed. Once all the melamine was dissolved, triethanolamine was added to the solution to reduce the pH to about 8. Subsequently, the solution was heated to 70°C in an oil bath, stirred for 1 h, which was mainly the addition reaction of melamine and formaldehyde under alkaline conditions to form a water-soluble transparent prepolymer A. 2 parts of aluminum diethylphosphinate and 2 parts of sodium dodecyl sulfate were dissolved in 120 parts of deionized water, 10 parts of fluorooctyl ethyl triethoxysilane and perfluorohexyl ethyl triethoxysilane were added, and 14 parts of toluene solution was added, stirred at room temperature for 25 minutes, and emulsified at a high speed of 2500 r / min to form a stable emulsion B. The prepolymer A and the emulsion B were placed in the dispersed phase container and the continuous phase container, and the emulsion B was slowly pushed into the prepolymer A under the air pressure of 11 kPa, and the stirring speed of the prepolymer A was 700 r / min. After the emulsion B was completely pushed into the prepolymer A, the solution was then adjusted to pH 5.5 with acetic acid, and the solution was reacted at 65°C for 4 hours to complete the condensation coating. Finally, the polymerization solution was washed with ethanol and deionized water several times to remove excess prepolymer A by centrifugation, and dried in a drying oven at 70°C for 40 hours to obtain self-repairing microcapsules.

[0058] Second step, preparation of phosphate coating:

[0059] 80 parts of a 55% mass fraction aqueous solution of aluminum phosphate AlPO4 and aluminum hypophosphite Al(PO2H2)3 solution and 10 parts of inorganic curing agent Al2O3 were mixed, 80 parts of deionized water were added, 4 parts of self-repairing microcapsules were added, and magnetic stirring was carried out at room temperature for 1 hour to obtain a self-repairing phosphate coating slurry. The substrate glass was degreased with ethanol for 20 minutes, washed with pure water for 2 times, and dried with nitrogen. Air spraying was carried out at 0.3 MPa, and the coating was sprayed onto the glass substrate, and gradient temperature curing was carried out in three times, and the temperature and time were 45°C, 22 minutes, 100°C, 40 minutes, and 185°C, 84 minutes, respectively.

[0060] Comparative Example 2: Microcapsules without adding repair function organosilane

[0061] First step, preparation of self-repairing melamine urea-formaldehyde resin microcapsules:

[0062] The melamine, formaldehyde and deionized water were stirred and mixed together. Once all the melamine was dissolved, triethanolamine was added to the solution to reduce the pH to about 9. The solution was then heated in an oil bath with stirring for 2 h. This step is primarily the addition reaction of melamine and formaldehyde under basic conditions to form a water-soluble transparent prepolymer A. 1.5 parts of aluminum diethylphosphinate and 1.5 parts of sodium dodecyl sulfate were dissolved in 120 parts of deionized water, 10 parts of toluene solution was added, stirred at room temperature for 20 minutes, emulsified to form a stable emulsion B at a high speed of 3500 r / min. The prepolymer A and emulsion B were placed in the dispersed phase container and the continuous phase container, and the emulsion B was slowly pushed into the prepolymer A under the air pressure of 14 kPa, and the stirring speed of the prepolymer A was 850 r / min. After the emulsion B was completely pushed into the prepolymer A, the solution was then adjusted to a pH of 5 with acetic acid, and the solution was reacted at 65°C for 2 hours to complete the condensation coating. Finally, the polymerization solution was washed several times with ethanol and deionized water to remove excess prepolymer A by centrifugation, and dried in a drying oven at 90°C for 44 hours to obtain self-repairing microcapsules.

[0063] Second step, preparation of phosphate coating:

[0064] The aluminum particles, 20 nm in diameter, were dispersed into a zirconium-based passivation solution with the components of zirconium sulfate (0.2 g / L), sodium tripolyphosphate (0.2 g / L), and organic acid (2.0 g / L), and the solution pH was 4.2. After 5 minutes of ultrasonic treatment, the passivated aluminum particles were collected by repeated washing with deionized water and filtration. 100 parts of a 65% mass fraction aluminum phosphate AlPO4 aqueous solution and 15 parts of magnesium oxide MgO were mixed, 110 parts of deionized water was added, 13 parts of passivated aluminum particles and 5 parts of self-repairing microcapsules were added, and the mixture was magnetically stirred at room temperature for 1 hour to obtain a self-repairing phosphate coating slurry. The substrate glass was degreased by ultrasonic treatment in ethanol for 30 minutes, washed with pure water for 3 times, and dried with nitrogen. The coating was sprayed onto the glass substrate using air spraying at 0.4 MPa, and was cured in three steps at gradient temperatures. 55°C for 25 minutes, 185°C for 58 minutes, and 190°C for 87 minutes.

[0065] Comparative Example 3: coating without self-repairing microcapsules

[0066] First step, preparation of phosphate coating:

[0067] Aluminum particles with a diameter of 40 nm were dispersed in a zirconium-based passivation solution. The solution consisted of zirconium sulfate (0.15 g / L), sodium tripolyphosphate (0.15 g / L), and organic acid (1.0 g / L), with a pH of 4. After ultrasonic treatment for 5 minutes, the solution was repeatedly rinsed with deionized water, and the passivated aluminum particles were collected by filtration. A 70% (w / w) aqueous solution of aluminum dihydrogen phosphate (Al(H2PO4)3) and aluminum hypophosphite (Al(PO2H2)3) was mixed with 18 parts of inorganic curing agents, alumina (Al2O3) and zinc oxide (ZnO). 115 parts of deionized water and 15 parts of passivated aluminum particles were added, and the mixture was magnetically stirred at room temperature for 2 hours to obtain the slurry for a self-healing phosphate coating. The substrate glass was degreased with ethanol, ultrasonicated for 40 minutes, washed four times with pure water, and dried with nitrogen. The coating was sprayed onto the glass substrate using 0.5 MPa air spraying and cured in three stages at a gradient temperature. 60℃, 30 minutes, 200℃, 60 minutes, 200℃, 90 minutes.

[0068] Test method:

[0069] 1) Take the cured sample and test the coating hardness using a micro Vickers hardness tester according to national standards. Test each sample five times and take the average value.

[0070] 2) The six groups of samples were placed in a 3.5 wt.% NaCl solution for a four-week water absorption test, and a weighing experiment was conducted every week.

[0071] Depend on Figure 1 It can be seen that Comparative Example 1 did not contain passivated aluminum particles, therefore the coating hardness was significantly lower than that of the other samples, with a hardness of only 358. The hardness of the other samples was greater than 400, with the lowest being Example 1 at 425. This indicates that the passivated aluminum particles significantly improved the coating hardness and mechanical properties. Figure 2 It can be seen that after the addition of microcapsules, the water absorption rate of the samples tended to be stable with little change from 2 to 4 weeks, except for the initial large amount of water reabsorption. The only one with a gradually increasing water absorption rate was the control sample 3, which did not have self-healing microcapsules added to its coating. The water absorption rate after 4 weeks was 2.7%, indicating that the addition of self-healing microcapsules to the phosphate coating significantly improves the protective performance and service life of the coating.

[0072] The present invention has been described above by way of example. It is obvious that the specific implementation of the present invention is not limited to the above-described manner. Any non-substantial improvements made using the inventive concept and technical solution, or the direct application of the inventive concept and technical solution to other situations without modification, are all within the protection scope of the present invention. The protection scope of the present invention should be determined by the scope defined in the claims.

Claims

1. A self-repairing microcapsule, characterized in that The following steps are adopted to prepare: ① 5-7 parts of melamine, 9-12 parts of formaldehyde and 25-35 parts of deionized water are stirred and mixed, and after all the melamine is dissolved, triethanolamine is added to the solution to reduce the pH to 8-10, to obtain a mixed solution; the mixed solution is heated and stirred in an oil bath, and the addition reaction under alkaline conditions forms a water-soluble transparent prepolymer A; ② 0.5-2 parts of aluminum diethylphosphinate and 0.5-2 parts of sodium dodecyl sulfate are dissolved in 100-120 parts of deionized water, 5-10 parts of organosilane and 8-14 parts of toluene are added, and the mixture is stirred at room temperature for 15-25 minutes to form a stable emulsion B; the prepolymer A and the emulsion B are placed in the dispersed phase container and the continuous phase container respectively, and the emulsion B is slowly pushed into the prepolymer A at a certain air pressure to obtain a polymerization solution; the pH of the polymerization solution is adjusted to be acidic with acetic acid, and the polymerization solution is reacted at 65-75℃ for 1-5 hours to complete the condensation coating; after washing, the excess prepolymer A is removed, and after drying, self-repairing microcapsules are obtained; The above parts refer to weight ratio.

2. The self-repairing microcapsule according to claim 1, characterized in that The heating temperature of the addition reaction in step ① is 65-75℃, and the stirring time is 1-2h.

3. The self-repairing microcapsule according to claim 1, wherein The organosilane in step ② is at least one of fluorooctyl ethyl triethoxysilane, heptadecafluorodecyl triethoxysilane, perfluorohexyl ethyl triethoxysilane and perfluorodecyl trimethoxysilane.

4. The self-repairing microcapsule according to claim 1, wherein The air pressure used to slowly push the emulsion B into the prepolymer A in step ② is 10-15kPa.

5. The self-repairing microcapsule according to claim 1, wherein The rotation speed of the emulsification in step ② is 2000-4000r / min.

6. The self-repairing microcapsule according to claim 1, wherein The pH of the polymerization solution in step ② is adjusted to 5-6 with acetic acid.

7. The self-repairing microcapsule according to claim 1, wherein The drying conditions in step ② are as follows: drying at 60-100℃ for 36-48 hours in a drying oven.

8. A phosphate coating having the self-repairing microcapsules according to any one of claims 1 to 7 applied thereto, characterized in that It comprises the following components and their weight ratios: Phosphate aqueous solution 80-120 parts; Inorganic curing agent 10-20 parts; Deionized water 80-120 parts; Passivated aluminum particles 10-20 parts; Self-repairing microcapsules 3-9 parts; The mass fraction of phosphate in the aforementioned phosphate aqueous solution is 50-70%.

9. The phosphate coating according to claim 8, characterized in that The passivated aluminum particles are prepared by the following steps: Disperse the aluminum particles into a zirconium-based passivation solution, ultrasonic treatment for 1-5 minutes, filter and collect the passivated aluminum particles, and rinse repeatedly with deionized water.

10. The phosphate coating according to claim 9, characterized in that The zirconium-based passivation solution is composed of the following components and their concentrations: zirconium sulfate 0.1-0.2g / L, sodium tripolyphosphate 0.1-0.2g / L, and organic acid 0.8-1.5g / L, and the pH of the zirconium-based passivation solution is 3.5-4.

2.

11. The phosphate coating of claim 9, wherein The aluminum particles are nano aluminum particles with a diameter of 10-50nm.

12. The phosphate coating of claim 8, wherein The phosphate is at least one of aluminum phosphate AlPO4, aluminum dihydrogen phosphate Al(H2PO4)3 and aluminum hypophosphite Al(PO2H2)3.

13. The phosphate coating of claim 8, wherein The inorganic curing agent is at least one of iron oxide Fe2O3, magnesium oxide MgO, aluminum oxide Al2O3 and zinc oxide ZnO.

14. A method of producing the phosphate coating according to any one of claims 8 to 13, characterized in that It comprises the following steps: Mixing phosphate aqueous solution and inorganic curing agent, adding deionized water, adding passivated aluminum particles and self-repairing microcapsules, and stirring magnetically at room temperature for 1-2 hours, a self-repairing phosphate coating original slurry can be obtained; Degreasing the substrate glass with ethanol for 20-40 minutes by ultrasonic, washing with pure water, and blowing dry with nitrogen; Spraying the coating onto the glass substrate by air spraying, and curing at gradient temperature to obtain a phosphate coating.

15. The method of claim 14, wherein The air spraying pressure is 0.3-0.5 MPa.

16. The method of claim 14, wherein The gradient curing temperature is three stages, 40-60℃, 100-120℃, and 180-200℃, respectively, and the curing time at each temperature stage is 20-30, 50-60, and 80-90 minutes, respectively.

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