An aerosol type water-based self-repairing coating, a preparation method and application thereof

Abstract

The application discloses a kind of gas mist type water-based self-repairing coating and its preparation method and application, the water-based self-repairing coating, by weight parts, including the following components: by weight parts including the following components: deionized water 10-30 parts, bactericide 0.1-0.5 parts, defoaming agent 0.1-0.5 parts, dispersing agent 1-2 parts, anti-settling agent 1-3 parts, anti-flash rust agent 0.5-1 part, modified zinc phosphate 5-10 parts, aluminum tripolyphosphate 5-15 parts, iron oxide red or iron titanium powder 5-10 parts, double-coated modified graphene microcapsule 10-35 parts, water-based nano fluorocarbon resin 20-40 parts, film-forming aid 1-5 parts, pH regulator 0.1-0.5 parts, propellant 1-5 parts.The gas mist type water-based self-repairing coating of the application can have high self-repairing width under normal temperature environment under the premise of reaching weather resistance and corrosion resistance, and has good environmental protection performance, is convenient to use by aerosol type packaging, and is more suitable for outdoor site construction.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of water-based paint, in particular to an aerosol type water-based self-repairing paint, a preparation method and application thereof. BACKGROUND

[0002] In the development of social economy, anticorrosive coatings play a great role in protecting the long-term normal operation of various infrastructures and provide high economic benefits, such as various marine equipment, land energy storage and transportation equipment, photovoltaic new energy support equipment, wind power support equipment, power transmission equipment, various smelting plant production equipment, etc. During use, local areas of anticorrosive coatings may be cracked and damaged due to various reasons. If not repaired, the equipment substrate will be directly exposed to various corrosive environments, causing corrosion of the substrate, and in severe cases, affecting the service life and normal operation of the equipment. However, a large amount of secondary maintenance will cause waste of manpower and materials.

[0003] Intelligent repair anticorrosive coatings can release relevant anticorrosive repair agents to repair the cracks within a certain range under certain conditions, saving costs for the long-term protection and subsequent maintenance of anticorrosive coatings. However, the currently available intelligent repair anticorrosive coatings cannot simultaneously guarantee excellent anticorrosion and weather protection performance, environmental protection performance, and convenient construction, as well as self-repairing under normal temperature conditions:

[0004] The commercially available smart repair anticorrosive coating generally uses light catalysis and high heat energy catalysis to excite the self-repair of the coating. However, due to the uncertainty of the light exposure time of the environment and the inconvenience of heating construction, the effective self-repair of the anticorrosive coating is limited. Therefore, the market urgently needs an anticorrosive coating that can automatically excite repair at room temperature. The repair range of the commercially available smart repair coating is within 100 μm, and it is difficult to fully repair beyond 100 μm. Therefore, there is a need for an anticorrosive coating that can automatically excite repair at room temperature and has a high repair range. The anticorrosive protection effect of the commercially available smart repair coating on the metal substrate is poor, and the neutral salt spray resistance is generally not more than 300 hours. The anticorrosive protection effect on the metal substrate is not more than 3 years. The weather resistance of the commercially available smart repair coating is poor, and the gloss and color retention are not more than 5 years. The commercially available smart repair anticorrosive paint is in a bucket, and it needs to be used with construction tools such as brushes, rollers and paint sprayers during construction, which is not very convenient. In addition, the cracked and damaged area of the anticorrosive coating is sometimes the inner wall of some special structure pipeline, corner and high-rise steel structure. It is difficult to use ordinary construction methods such as brushing. The construction efficiency is low, and there are problems such as hidden corners of missed coating, large waste of construction materials (such as air spraying), etc. In addition, many commercially available anticorrosive repair coatings are solvent-based, which not only causes damage to the natural environment due to high VOC content, but also causes combustion accidents in some mine tunnels and relatively closed environments. The volatilization of solvents will cause damage to equipment, property, human life and health, and the natural environment.

[0005] Therefore, there is an urgent need for an aerosol type water-based smart self-repair metal anticorrosive coating to solve the above problems. SUMMARY

[0006] In view of the defects in the prior art, the present application provides an aerosol type water-based self-repair coating, a preparation method and application thereof.

[0007] The application provides an aerosol type water-based paint, which comprises the following components by weight parts: deionized water 10-30 parts, such as 10, 15, 20, 25, 30 parts; bactericide 0.1-0.5 parts, such as 0.1, 0.2, 0.3, 0.4, 0.5 parts; defoamer 0.1-0.5 parts, such as 0.1, 0.2, 0.3, 0.4, 0.5 parts; dispersant 1-2 parts, such as 1, 1.2, 1.4, 1.6, 1.8, 2.0 parts; anti-settling agent 1-3 parts, such as 1, 1.5, 2, 2.5, 3 parts; anti-flash rust agent 0.5-1 parts, such as 0.5, 0.6, 0.7, 0.8, 0.9, 1 parts; modified zinc phosphate 5-10 parts, such as 5, 6, 7, 8, 9, 10 parts; aluminum tripolyphosphate 5-15 parts, such as 5, 8, 10, 12, 15 parts; iron oxide red or iron titanium powder 5-10 parts, such as 5, 6, 7, 8, 9, 10 parts; double-coated modified graphene microcapsule 10-35 parts, such as 10, 15, 20, 25, 30, 35 parts; water-based nano fluorocarbon resin 20-40 parts, such as 20, 25, 30, 35, 40 parts; film-forming aid 1-5 parts, such as 1, 2, 3, 4, 5 parts; pH adjuster 0.1-0.5 parts, such as 0.1, 0.2, 0.3, 0.4, 0.5 parts; propellant 1-5 parts, such as 1, 2, 3, 4, 5 parts.

[0008] Further, the double-coated modified graphene microcapsule comprises the following components by weight parts: deionized water 30-70 parts, such as 30, 40, 50, 60, 70 parts; modified graphene powder 5-20 parts, such as 5, 10, 15, 20 parts; water-based silicone modified acrylic resin 50-70 parts, such as 50, 55, 60, 65, 70 parts; 2.0wt% ethyl methacrylate 1-5 parts, such as 1, 2, 3, 4, 5 parts; urea 0.1-1 parts, such as 0.1, 0.2, 0.4, 0.5, 0.6, 0.8, 1 parts; ammonium chloride 0.01-1 parts, such as 0.01, 0.05, 0.1, 0.5, 1 parts; resorcinol 0.01-1 parts, such as 0.01, 0.05, 0.1, 0.5, 1 parts; 10wt% NaOH solution 0.01-1 parts, such as 0.01, 0.05, 0.1, 0.5, 1 parts; secondary octanol 1-5 parts, such as 1, 2, 3, 4, 5 parts; castor oil 50-70 parts, such as 50, 55, 60, 65, 70 parts; 30wt% formaldehyde solution 0.1-1 parts, such as 0.01, 0.05, 0.1, 0.5, 1 parts.

[0009] Further, the modified graphene powder comprises the following components by weight: 20-30 parts of graphene oxide, such as 20, 22, 24, 26, 28, 30 parts; 5-10 parts of citric acid, such as 5, 6, 7, 8, 9, 10 parts; 20-30 parts of ethanol, such as 20, 22, 24, 26, 28, 30 parts; 10-20 parts of titanate coupling agent, such as 10, 12, 14, 16, 18, 20 parts; 30-50 parts of hydrazine hydrate solution, such as 30, 35, 40, 45, 50 parts.

[0010] Further, the titanate coupling agent is selected from at least one of a single-alkoxy type titanate coupling agent, a chelate type titanate coupling agent, and a coordination type titanate coupling agent.

[0011] Further, the double-coated modified graphene microcapsule is 15-25 parts by weight, such as 15, 18, 20, 22, 25 parts.

[0012] Further, the modified graphene powder is 10-15 parts by weight, such as 10, 11, 12, 13, 14, 15 parts.

[0013] Further, the preparation method of the modified graphene powder is as follows:

[0014] The graphene oxide, citric acid, and ethanol are weighed by weight parts and pre-mixed, the mixture is dispersed by ultrasonic wave to obtain a uniformly dispersed graphene oxide dispersion liquid, the titanate coupling agent and the hydrazine hydrate solution are added into the graphene oxide dispersion liquid respectively, and the reaction occurs under the condition of 50-60℃ water bath heating, so that the graphene oxide is reduced and the titanate coupling agent polar molecules are grafted at the same time;

[0015] The obtained mixed liquid is filtered to remove impurities and vacuum dried, and finally the powder-shaped modified graphene powder is obtained.

[0016] Optionally, the graphene oxide has an oxygen content of 34-36% and a particle size of 20-30μm.

[0017] Optionally, the content of hydrazine hydrate in the hydrazine hydrate aqueous solution is 49-51%.

[0018] The van der Waals force between common graphene oxide is large, the dispersion stability in water is poor, easy to agglomerate, and the adhesion to the substrate is poor, which cannot fully play the anticorrosion protection function of the substrate. The surface of graphene is modified by using titanate coupling agent, which can form polar groups, so that the modified graphene can be uniformly and stably dispersed in water, and then a suspension stable microcapsule liquid is prepared; by using the good hydrophobic property of graphene, the penetration of water, oxygen, chloride ions and other substances in the environment is blocked, and at the same time, the structure of two-dimensional sheet layer is stacked to form a labyrinth barrier, which hinders the penetration path of corrosion medium and blocks the path of primary cell formation, thereby delaying the corrosion rate of the substrate; by using the mechanical properties of graphene, the elasticity and deformation resistance of the coating are improved by combining with the film-forming resin, the wear resistance of the coating is increased, and the service life of the coating is prolonged.

[0019] Further, the preparation method of the double-coated modified graphene microcapsule is as follows:

[0020] The mixed solution is prepared by weighing 10-30 parts of deionized water and modified graphene powder into a container, stirring thoroughly, then adding water-based silicone modified acrylic resin and mixing uniformly, filtering the uniformly dispersed mixed solution to obtain the mixed solution.

[0021] The emulsion is prepared by weighing 20-40 parts of deionized water and 2.0wt% of ethyl methacrylate aqueous solution into a container, stirring at a speed of 300-400r / min, then adding urea, ammonium chloride and resorcinol, adjusting the pH value of the mixture to 8.5-9.0 with 10wt% NaOH solution, then adding sec-octyl alcohol emulsion dropwise, finally adding castor oil, heating to 40-50℃, stirring and emulsifying for 25-30 minutes to form a uniform emulsion, and cooling to room temperature to obtain the emulsion.

[0022] The emulsion is prepared by weighing 20-40 parts of deionized water and 2.0wt% of ethyl methacrylate aqueous solution into a container, stirring at a speed of 300-400r / min, then adding urea, ammonium chloride and resorcinol, adjusting the pH value of the mixture to 8.5-9.0 with 10wt% NaOH solution, then adding sec-octyl alcohol emulsion dropwise, finally adding castor oil, heating to 40-50℃, stirring and emulsifying for 25-30 minutes to form a uniform emulsion, and cooling to room temperature to obtain the emulsion.

[0023] The emulsion is prepared by weighing 20-40 parts of deionized water and 2.0wt% of ethyl methacrylate aqueous solution into a container, stirring at a speed of 300-400r / min, then adding urea, ammonium chloride and resorcinol, adjusting the pH value of the mixture to 8.5-9.0 with 10wt% NaOH solution, then adding sec-octyl alcohol emulsion dropwise, finally adding castor oil, heating to 40-50℃, stirring and emulsifying for 25-30 minutes to form a uniform emulsion, and cooling to room temperature to obtain the emulsion.

[0024] The emulsion is prepared by weighing 20-40 parts of deionized water and 2.0wt% of ethyl methacrylate aqueous solution into a container, stirring at a speed of 300-400r / min, then adding urea, ammonium chloride and resorcinol, adjusting the pH value of the mixture to 8.5-9.0 with 10wt% NaOH solution, then adding sec-octyl alcohol emulsion dropwise, finally adding castor oil, heating to 40-50℃, stirring and emulsifying for 25-30 minutes to form a uniform emulsion, and cooling to room temperature to obtain the emulsion.

[0025] Optionally, the solid content of the water-based silicone modified acrylic resin is 50.0-60.0%, and the pH value is 8.0-10.0.

[0026] Optionally, the nitrogen content of the urea is ≥46.0%, and the purity is ≥98.5%.

[0027] When the coating cracks, the double-coated modified graphene microcapsules (silicone-modified acrylic resin and castor oil coating) in the coating are also broken under force, since the castor oil has excellent fluidity and permeability at room temperature and low temperature, it can impart excellent peristalsis fluidity to the microcapsules, and the silicone-modified acrylic resin as the inner cavity layer in the double-coated structure increases the wall thickness and elasticity of the double-coated structure microcapsules, further improving the peristalsis fluidity of the microcapsules, so that the modified graphene in the microcapsules can be more widely and uniformly distributed in the cracked damage area, greatly improving the self-repairing range of the coating.

[0028] The coating after cracking repair also has excellent weather resistance, heat resistance, chemical corrosion resistance and low temperature protection performance, as well as self-cleaning function, and the light resistance, weather resistance and aging resistance of polyacrylate, and the excellent heat resistance, chemical resistance, insulation corrosion resistance, low temperature resistance, impact resistance, wear resistance and easy cleaning type of the Si-O strong bond energy (444KJ / m) and other unique structures of the silicone structure, so that the self-repairing coating of the microcapsules after cracking has a durable protection performance of more than 20 years.

[0029] The polar functional groups on the surface of graphene and the hydroxyl polar groups of castor oil can form hydrogen bonds or chemical bonds with the surface of the steel substrate, increase the adhesion, and enable the substrate to be firmly combined with the surface of the substrate, and the high dielectric constant of castor oil can impart insulation between the substrate and the electrolyte, further delaying the electrochemical corrosion rate of the steel substrate.

[0030] The application also provides a preparation method of the water-based paint, comprising the following steps:

[0031] Deionized water, bactericide, defoaming agent, dispersant, anti-settling agent and anti-flash rust agent are weighed by weight parts and sequentially added into a container, and mixed uniformly under low-speed stirring at 300-500 r / min, then modified zinc phosphate, aluminum tripolyphosphate and iron oxide red or iron titanium powder are sequentially added and mixed uniformly under medium-speed stirring at 500-800 r / min, and then ground in a horizontal sand mill for more than 1 hour to make the fineness ≤30 μm;

[0032] The ground pigment slurry is added into the container, and the self-made double-coated modified graphene microcapsules, water-based nano fluorocarbon resin and film-forming aid weighed by weight parts are slowly added, and mixed for 10-15 min under low-speed stirring at 300-500 r / min to ensure uniform stirring and mixing, and finally the pH regulator is added to adjust the pH value to 8.5-9.0, to obtain the water-based paint liquid;

[0033] The prepared water-based coating liquid is filtered through a 320-330 mesh filter screen, and then according to the filling amount of the aerosol, the coating liquid and the propellant are filled into the aerosol tank with an anticorrosive coating on the inner wall in a proportion, an aerosol valve with an anticorrosive coating is installed, the tank is sealed by an aerosol special sealing machine, nitrogen propellant is filled into the tank by an aerosol special inflator according to the formula proportion, and an atomizing nozzle is installed to produce an aerosol type water-based intelligent self-repairing metal anticorrosive coating with excellent performance.

[0034] The bactericide includes but is not limited to one or more of Dow Chemical KATHON LX150, Rhone BIT20, Hofmann D35, A325, A379.

[0035] The defoaming agent includes but is not limited to one or more of Degussa Tego902, Tego810, Dow Chemical NDW, Blacken CF246.

[0036] Optionally, the dispersant is a water-based high molecular acrylic block dispersant, including but not limited to any one of BYK190 of Bichemical, Tego750, Tego755, Afcona-4550, Afcona-4560 of Degussa.

[0037] Optionally, the anti-settling agent is a fumed silica, a water-based bentonite or a water-based polyamide wax anti-settling agent, including but not limited to one or more of Cabot M5, Fenghong SMP-K, Desbon AQ600, AQ630.

[0038] The anti-flash rust agent includes but is not limited to any one of RABO60 of Ruibao, Hymns FA170, Enze Chemical HY71.

[0039] Optionally, the modified zinc phosphate residue is 300-400 mesh, and the oil absorption value is 35-40, which can be selected from any one of a high molecular modified zinc phosphate or an aluminum ion modified zinc phosphate.

[0040] Optionally, the aluminum tripolyphosphate residue is 300-400 mesh, and the oil absorption value is 25-30.

[0041] Optionally, the iron-titanium powder residue is 500-600 mesh, and the oil absorption value is 15-25.

[0042] Optionally, the water-based nano fluorocarbon resin has a fluorine content of ≥20%, a solid content of ≥50%, a C-F strong bond energy (485 KJ / m) in the water-based nano fluorocarbon resin, and a "nano effect" of nano structure material, so that the water-based nano fluorocarbon resin has more excellent light, heat and chemical stability, and use in the coating can make the coating maintain gloss and color, improve the weather resistance, acid rain resistance, salt fog corrosion resistance, low temperature cracking and deformation resistance and hydrophobic self-cleaning function of the coating.

[0043] Optionally, the pH regulator is of the type of high-molecular organic amine compound, including but not limited to any one of Dow AMP95, BASF BDEOA.

[0044] Optionally, the film-forming aid is a strong solvent of ether alcohol polymer, including but not limited to any one of alcohol ester twelve or texanol.

[0045] Optionally, the propellant is nitrogen.

[0046] The present application replaces a large amount of organic solvents with water, and uses environmentally friendly and non-flammable nitrogen as the propellant, which will not cause safety accidents such as combustion and explosion in relatively closed systems such as mine tunnels or storage tanks, thereby protecting equipment, property, human life and health, and the environment, and the non-flammability makes transportation and storage safer; and the aerosol type packaging of the anticorrosive coating can avoid the problems such as low construction efficiency, hidden dangers of missed coating and corners, and large waste of construction materials (such as air spraying) caused by ordinary construction methods (such as brushing) in some special structure pipelines, corners and high-rise steel structures.

[0047] The present application utilizes the cooperation of each component of the formula and the synergistic effect with the rust-proof pigment to jointly improve the comprehensive anticorrosive performance of the coating.

[0048] The present application also provides the application of the water-based coating as a self-repairing coating for metal substrates.

[0049] In summary, compared with the prior art, the present application achieves the following technical effects:

[0050] 1) The water-based coating provided by the present application can automatically repair and fill in the cracks of the coating with a width range of 100-300 μm at room temperature.

[0051] 2) The water-based coating provided by the present application has excellent anticorrosive protection function.

[0052] 3) The water-based coating provided by the present application and the repaired coating both have excellent weather resistance, heat resistance, chemical corrosion resistance, low-temperature protection performance and self-cleaning function.

[0053] 4) The water-based coating provided by the present application has excellent ultra-low VOC environmental protection function and non-flammability.

[0054] 5) The water-based coating provided by the present application is packaged in an aerosol type, which is convenient for construction and use and can save materials. BRIEF DESCRIPTION OF DRAWINGS

[0055] In order to make the technical solutions of the embodiments of the present application clearer, the following will briefly introduce the drawings needed to be used in the embodiments. It should be understood that the following drawings only show some embodiments of the present application, and therefore should not be regarded as a limitation on the scope. For those skilled in the art, other related drawings can also be obtained without creative labor.

[0056] Figure 1 The self-repairing scanning electron microscope image of the paint scratch with a width of 300 μm prepared for the present application embodiment 2;

[0057] Figure 2 The self-repairing scanning electron microscope image of the paint scratch with a width of 300 μm prepared for the present application comparative example 1. DETAILED DESCRIPTION

[0058] In order to make the technical solutions of the embodiments of the present application clearer, the following will briefly introduce the drawings needed to be used in the embodiments. It should be understood that the following drawings only show some embodiments of the present application, and therefore should not be regarded as a limitation on the scope. For those skilled in the art, other related drawings can also be obtained without creative labor.

[0059] EMBODIMENT

[0060] The following will further illustrate the present application by combining specific embodiments and comparative examples. The following specific embodiments are preferred embodiments of the present application, but the embodiments of the present application are not limited by the following examples, and in particular are not limited to the types of raw materials used in the following specific examples.

[0061] I. Raw material sources

[0062] The raw materials of the embodiments and comparative examples are all commercially available unless otherwise specified. Among them, the ammonium chloride should be a first-class industrial product, the castor oil should be a first-class industrial product, the quality requirements should meet the requirements in GB8234-2019, and the iron oxide red should meet the first-class product requirements in the national standard GB1863-89;

[0063] Modified graphene powder #1: self-made, the preparation method is as follows:

[0064] Pre-mix 25 parts of graphene oxide, 7 parts of citric acid and 20 parts of ethanol, disperse the mixture by ultrasonic wave to obtain a uniformly dispersed graphene oxide dispersion, add 13 parts of titanate coupling agent and 35 parts of hydrazine hydrate solution into the graphene oxide dispersion, and react under the condition of 50-60℃ water bath heating to reduce the graphene oxide and simultaneously graft the polar molecules of the titanate coupling agent; filter the obtained mixture, remove the impurities and vacuum dry to obtain modified graphene powder #1;

[0065] Modified graphene powder #2: self-made, the preparation method is as follows:

[0066] Pre-mix 25 parts of graphene oxide, 5 parts of citric acid and 30 parts of ethanol, disperse the mixture by ultrasonic wave to obtain a uniformly dispersed graphene oxide dispersion, add 10 parts of titanate coupling agent and 30 parts of hydrazine hydrate solution into the graphene oxide dispersion, and react under the condition of 50-60℃ water bath heating to reduce the graphene oxide and simultaneously graft the polar molecules of the titanate coupling agent; filter the obtained mixture, remove the impurities and vacuum dry to obtain modified graphene powder #2;

[0067] Modified graphene powder #3: self-made, the preparation method is as follows:

[0068] Pre-mix 25 parts of graphene oxide, 10 parts of citric acid and 25 parts of ethanol, disperse the mixture by ultrasonic wave to obtain a uniformly dispersed graphene oxide dispersion, add 15 parts of titanate coupling agent and 25 parts of hydrazine hydrate solution into the graphene oxide dispersion, and react under the condition of 50-60℃ water bath heating to reduce the graphene oxide and simultaneously graft the polar molecules of the titanate coupling agent; filter the obtained mixture, remove the impurities and vacuum dry to obtain modified graphene powder #3;

[0069] Double-coated modified graphene microcapsule #1: self-made, the preparation method is as follows:

[0070] Mixed solution:

[0071] Weigh 25 parts of deionized water, 10 parts of modified graphene powder #1 and 65 parts of water-based silicone modified propylene resin into a container in sequence, mix them uniformly after fully stirring, filter the uniformly dispersed mixed solution to obtain a mixed solution;

[0072] Emulsion:

[0073] Take 29.7 parts of deionized water and 2 parts of 2.0 wt% ethyl methacrylate aqueous solution by weight, add them into the container in turn, and add 0.5 parts of urea, 0.1 parts of ammonium chloride and 0.1 parts of resorcinol under stirring at a speed of 300 r / min, mix them uniformly, adjust the pH value of the mixture to 8.5 with 10 wt% NaOH solution, then add 2 parts of secondary octanol emulsion dropwise, finally add 65 parts of castor oil, heat to 40℃, and emulsify for 25 minutes under stirring to form a uniform emulsion, cool to room temperature to obtain the emulsion;

[0074] Mix the mixed solution and the emulsion, stir at a speed of 9000 r / min for 20 minutes, then add 0.5 parts of 30 wt% formaldehyde solution, raise the temperature of the mixture to 55℃ and maintain for 3.5 hours to form a uniform and stable microcapsule suspension, cool the suspension to room temperature, and filter by vacuum filtration technology to obtain the double-coated modified graphene microcapsule #1.

[0075] Double-coated modified graphene microcapsule #2: self-made, the preparation method is as follows:

[0076] Mixed solution:

[0077] Take 25 parts of deionized water and 10 parts of modified graphene powder #2 by weight, add them into the container in turn, stir thoroughly, then add 52 parts of water-based silicone modified propylene resin and mix them uniformly to form a uniformly dispersed mixed solution, and filter to obtain the mixed solution;

[0078] Emulsion:

[0079] Take 29.7 parts of deionized water and 2 parts of 2.0 wt% ethyl methacrylate aqueous solution by weight, add them into the container in turn, and add 0.5 parts of urea, 0.1 parts of ammonium chloride and 0.1 parts of resorcinol under stirring at a speed of 350 r / min, mix them uniformly, adjust the pH value of the mixture to 9.0 with 10 wt% NaOH solution, then add 2 parts of secondary octanol emulsion dropwise, finally add 70 parts of castor oil, heat to 50℃, and emulsify for 30 minutes under stirring to form a uniform emulsion, cool to room temperature to obtain the emulsion;

[0080] Mix the mixed solution and the emulsion, stir at a speed of 8000 r / min for 15 minutes, then add 0.5 parts of 30 wt% formaldehyde solution, raise the temperature of the mixture to 60℃ and maintain for 4 hours to form a uniform and stable microcapsule suspension, cool the suspension to room temperature, and filter by vacuum filtration technology to obtain the double-coated modified graphene microcapsule #2.

[0081] Double-coated modified graphene microcapsule #3: self-made, the preparation method is as follows:

[0082] Mixed solution:

[0083] Take 25 parts of deionized water, 10 parts of modified graphene powder #3 by weight, and add 70 parts of water-based silicone modified propylene resin and mix uniformly, form a uniformly dispersed mixture, and filter to obtain a mixture;

[0084] Emulsion:

[0085] Take 29.7 parts of deionized water and 2 parts of 2.0wt% ethyl methacrylate aqueous solution by weight, and add 0.5 parts of urea, 0.1 parts of ammonium chloride and 0.1 parts of resorcinol under stirring at 400r / min, and mix uniformly, adjust the pH value of the mixture to 8.5 with 10wt% NaOH solution, then add 2 parts of secondary octanol emulsion, and finally add 52 parts of castor oil, constant temperature heating to 50℃, stirring emulsification 30 minutes, forming a uniform emulsion, cooling to room temperature to obtain the emulsion;

[0086] Mix the mixture and the emulsion, stir at 1000r / min for 20 minutes, then add 0.5 parts of 30wt% formaldehyde solution, raise the temperature of the mixture to 60℃ and maintain for 4 hours, form a uniform and stable microcapsule suspension, cool the suspension to room temperature, and filter with vacuum filtration technology to obtain double-coated modified graphene microcapsule #3.

[0087] Double-coated modified graphene microcapsule #4: self-made, the preparation method is as follows:

[0088] Mixture:

[0089] Take 25 parts of deionized water, 10 parts of unmodified graphene oxide powder by weight, and add 65 parts of water-based silicone modified propylene resin and mix uniformly, form a uniformly dispersed mixture, and filter to obtain a mixture;

[0090] Emulsion:

[0091] Take 29.7 parts of deionized water and 2 parts of 2.0wt% ethyl methacrylate aqueous solution by weight, and add 0.5 parts of urea, 0.1 parts of ammonium chloride and 0.1 parts of resorcinol under stirring at 300r / min, and mix uniformly, adjust the pH value of the mixture to 8.5 with 10wt% NaOH solution, then add 2 parts of secondary octanol emulsion, and finally add 65 parts of castor oil, constant temperature heating to 50℃, stirring emulsification 30 minutes, forming a uniform emulsion, cooling to room temperature to obtain the emulsion;

[0092] The mixed solution and the emulsion are mixed, 0.5 parts of 30wt% formaldehyde solution is added after stirring at a speed of 1000r / min for 20 minutes, the temperature of the mixture is raised to 60°C and maintained for 4 hours, a uniform and stable microcapsule suspension is formed, the suspension is cooled to room temperature and filtered by vacuum filtration technology, and a double-coated modified graphene microcapsule #4 is obtained.

[0093] II. Performance test methods

[0094] (1) Self-repairing width test: the repair degree of scratch width is observed by SEM scanning electron microscope;

[0095] (2) Paint film thickness test: test according to GBT13452.2-2008;

[0096] (3) Paint film weather resistance test: test according to GB / T1865-2009;

[0097] (4) Paint film neutral salt spray resistance test: test according to GB / T1771-2017;

[0098] (5) Paint film surface dry time test: test according to GB / T1728-1989;

[0099] (6) Paint film adhesion test: test according to GB / T9286-1998;

[0100] (7) Paint film appearance test: judge by visual observation;

[0101] (8) Storage stability test: observe the water-based paint in 50°C oven every week and every month.

[0102] Example 1

[0103] 26.8 parts of deionized water, 0.3 parts of bactericide, 0.4 parts of defoamer, 1 part of dispersant, 2 parts of anti-settling agent, 0.8 parts of anti-flash rust agent are sequentially added to a container, mixed uniformly under low-speed stirring of 300-500r / min, 5 parts of modified zinc phosphate, 8 parts of aluminum tripolyphosphate and 6 parts of red iron oxide are sequentially added, mixed uniformly under medium-speed stirring of 500-800r / min, and then ground in a horizontal sand mill for more than 1 hour to make fineness ≤30μm;

[0104] The ground pigment slurry is added to a container, 15 parts of self-made double-coated modified graphene microcapsule #1, 32 parts of water-based nano fluorocarbon resin and 2 parts of film-forming aid are slowly added, mixed for 10-15min under low-speed stirring of 300-500r / min to ensure uniform stirring and mixing, and finally a pH adjuster is added to adjust the pH value to 8.5-9.0, to obtain a water-based paint solution;

[0105] The prepared water-based coating liquid 200 grams is filtered with a 325 mesh filter and filled into a 500 ml aerosol can with an anticorrosive coating on the inner wall, an aerosol valve with an anticorrosive coating is installed, and after sealing with an aerosol special sealing machine, 3 grams of nitrogen propellant is filled in proportion with an aerosol special inflator, and an atomizing nozzle is installed to make an excellent aerosol type water-based intelligent self-repairing metal anticorrosive coating.

[0106] Example 2

[0107] In a container, 21.8 parts of deionized water, 0.3 parts of a bactericide, 0.4 parts of a defoaming agent, 1 part of a dispersing agent, 2 parts of an anti-settling agent, and 0.8 parts of an anti-flash rust agent are sequentially added and mixed uniformly under low-speed stirring at 300-500 r / min. Then, 5 parts of modified zinc phosphate, 8 parts of aluminum tripolyphosphate, and 5 parts of iron-titanium powder are sequentially added and mixed uniformly under medium-speed stirring at 500-800 r / min. After that, the mixture is ground in a horizontal sand mill for more than 1 hour to achieve a fineness of ≤30 μm.

[0108] The ground pigment slurry is added to a container, and 20 parts of self-made double-coated modified graphene microcapsule #1, 32 parts of water-based nano fluorocarbon resin, and 2 parts of a film-forming aid are slowly added. The mixture is stirred at 300-500 r / min for 10-15 min to ensure uniform stirring. Finally, a pH adjuster is added to adjust the pH value to 8.5-9.0 to obtain a water-based coating liquid.

[0109] The prepared water-based coating liquid 200 grams is filtered with a 325 mesh filter and filled into a 500 ml aerosol can with an anticorrosive coating on the inner wall, an aerosol valve with an anticorrosive coating is installed, and after sealing with an aerosol special sealing machine, 3 grams of nitrogen propellant is filled in proportion with an aerosol special inflator, and an atomizing nozzle is installed to make an excellent aerosol type water-based intelligent self-repairing metal anticorrosive coating.

[0110] Figure 1 The self-repairing scanning electron microscope image of the coating prepared in Example 2 at a scratch width of 300 μm shows that the coating of Example 2 can achieve full repair at a scratch width of 300 μm.

[0111] Example 3

[0112] In a container, 26.8 parts of deionized water, 0.3 parts of a bactericide, 0.4 parts of a defoaming agent, 1 part of a dispersing agent, 2 parts of an anti-settling agent, and 0.8 parts of an anti-flash rust agent are sequentially added and mixed uniformly under low-speed stirring at 300-500 r / min. Then, 5 parts of modified zinc phosphate, 8 parts of aluminum tripolyphosphate, and 5 parts of red iron oxide are sequentially added and mixed uniformly under medium-speed stirring at 500-800 r / min. After that, the mixture is ground in a horizontal sand mill for more than 1 hour to achieve a fineness of ≤30 μm.

[0113] The ground pigment slurry is added to a container, and then 15 parts of the self-made double-coated modified graphene microcapsule #2, 32 parts of the water-based nano fluorocarbon resin, and 2 parts of the film-forming aid are slowly added and mixed at a low speed of 300-500 r / min for 10-15 min to ensure uniform mixing. Finally, the pH regulator is added to adjust the pH value to 8.5-9.0, and a water-based paint solution is obtained.

[0114] The prepared water-based paint solution of 200 g is filtered through a 325-mesh filter screen and filled into a 500-mL aerosol tank with an anticorrosive coating on the inner wall. An aerosol valve with an anticorrosive coating is installed, and the tank is sealed with an aerosol-specific sealing machine. Then, 3 g of nitrogen propellant is filled into the tank using an aerosol-specific gas charger, and an atomizing nozzle is installed to obtain an aerosol-type water-based intelligent self-repairing metal anticorrosive coating with excellent performance.

[0115] Example 4

[0116] The deionized water, bactericide, defoamer, dispersant, anti-settling agent, and anti-flash rust agent are sequentially added to a container and mixed uniformly at a low speed of 300-500 r / min. Then, the modified zinc phosphate, aluminum tripolyphosphate, and iron oxide red are sequentially added and mixed uniformly at a medium speed of 500-800 r / min. After that, the mixture is ground in a horizontal sand mill for more than 1 hour to obtain a fine powder with a fineness of ≤30 μm.

[0117] The ground pigment slurry is added to a container, and then 15 parts of the self-made double-coated modified graphene microcapsule #2, 32 parts of the water-based nano fluorocarbon resin, and 2 parts of the film-forming aid are slowly added and mixed at a low speed of 300-500 r / min for 10-15 min to ensure uniform mixing. Finally, the pH regulator is added to adjust the pH value to 8.5-9.0, and a water-based paint solution is obtained.

[0118] The prepared water-based paint solution of 200 g is filtered through a 325-mesh filter screen and filled into a 500-mL aerosol tank with an anticorrosive coating on the inner wall. An aerosol valve with an anticorrosive coating is installed, and the tank is sealed with an aerosol-specific sealing machine. Then, 3 g of nitrogen propellant is filled into the tank using an aerosol-specific gas charger, and an atomizing nozzle is installed to obtain an aerosol-type water-based intelligent self-repairing metal anticorrosive coating with excellent performance.

[0119] Example 5

[0120] Put 26.8 parts of deionized water, 0.3 parts of fungicide, 0.4 parts of defoaming agent, 1 part of dispersing agent, 2 parts of anti-settling agent, 0.8 parts of anti-flash rust agent into the container in turn, mix uniformly under low speed stirring of 300-500 r / min, then add 5 parts of modified zinc phosphate, 8 parts of aluminum tripolyphosphate and 5 parts of iron titanium powder in turn, mix uniformly under medium speed stirring of 500-800 r / min, and then enter the horizontal sand mill for grinding for more than 1 hour to make fineness≤30 μm;

[0121] Put the ground pigment slurry into the container, then slowly add 15 parts of self-made double-coated modified graphene microcapsule #3, 32 parts of water-based nano fluorocarbon resin and 2 parts of film-forming aid, mix for 10-15 min under low speed stirring of 300-500 r / min to ensure uniform stirring and mixing, finally add pH regulator to adjust the pH value to 8.5-9.0 to obtain water-based paint liquid;

[0122] Filter 200 grams of the above prepared water-based paint liquid with a 325 mesh filter screen, fill it into a 500 ml aerosol tank with a corrosion-resistant coating on the inner wall, install a corrosion-resistant aerosol valve, seal it with an aerosol special sealing machine, then fill in 3 grams of nitrogen propellant in proportion with an aerosol special inflator, install an atomizing nozzle to make a water-based intelligent self-repairing metal anticorrosive coating with excellent performance in aerosol form.

[0123] Example 6

[0124] Put 26.8 parts of deionized water, 0.3 parts of fungicide, 0.4 parts of defoaming agent, 1 part of dispersing agent, 2 parts of anti-settling agent, 0.8 parts of anti-flash rust agent into the container in turn, mix uniformly under low speed stirring of 300-500 r / min, then add 5 parts of modified zinc phosphate, 8 parts of aluminum tripolyphosphate and 5 parts of iron titanium powder in turn, mix uniformly under medium speed stirring of 500-800 r / min, and then enter the horizontal sand mill for grinding for more than 1 hour to make fineness≤30 μm;

[0125] Put the ground pigment slurry into the container, then slowly add 15 parts of self-made double-coated modified graphene microcapsule #3, 32 parts of water-based nano fluorocarbon resin and 2 parts of film-forming aid, mix for 10-15 min under low speed stirring of 300-500 r / min to ensure uniform stirring and mixing, finally add pH regulator to adjust the pH value to 8.5-9.0 to obtain water-based paint liquid;

[0126] Filter 200 grams of the above prepared water-based paint liquid with a 325 mesh filter screen, fill it into a 500 ml aerosol tank with a corrosion-resistant coating on the inner wall, install a corrosion-resistant aerosol valve, seal it with an aerosol special sealing machine, then fill in 3 grams of nitrogen propellant in proportion with an aerosol special inflator, install an atomizing nozzle to make a water-based intelligent self-repairing metal anticorrosive coating with excellent performance in aerosol form.

[0127] Comparative Example 1

[0128] 21.8 parts of deionized water, 0.3 parts of a bactericide, 0.4 parts of an antifoaming agent, 1 part of a dispersing agent, 2 parts of an anti-settling agent, and 0.8 parts of an anti-flash rust agent were sequentially added into a container and mixed uniformly under low-speed stirring at 300-500 r / min, 5 parts of modified zinc phosphate, 8 parts of aluminum tripolyphosphate, and 5 parts of iron-titanium powder were sequentially added and mixed uniformly under medium-speed stirring at 500-800 r / min, and then the mixture was ground in a horizontal sand mill for more than 1 hour to obtain a pigment slurry with a fineness of ≤30 μm;

[0129] The ground pigment slurry was added into a container, 20 parts of self-made double-coated modified graphene microcapsule #4, 32 parts of water-based nano-fluorocarbon resin, and 2 parts of a film-forming aid were slowly added, and mixed for 10-15 min under low-speed stirring at 300-500 r / min to ensure uniform mixing, and finally a pH adjuster was added to adjust the pH value to 8.5-9.0 to obtain a water-based paint solution;

[0130] 200 g of the prepared water-based paint solution was filtered through a 325-mesh filter screen and filled into a 500-ml aerosol can with a corrosion-resistant coating on the inner wall, an aerosol valve with a corrosion-resistant coating was installed, the aerosol can was sealed with an aerosol special sealing machine, 3 g of nitrogen propellant was filled into the aerosol can according to the proportion with an aerosol special inflator, and an atomizing nozzle was installed to prepare an aerosol-type water-based intelligent self-repairing metal anticorrosive coating with excellent performance.

[0131] Figure 2 The self-repairing scanning electron microscope image of the coating prepared in Comparative Example 1 at a scratch width of 300 μm showed that the coating of Comparative Example 2 could only repair 100 μm at a scratch width of 300 μm, the un-repaired width was 200 μm, and full repair could not be achieved.

[0132] Table 1 below shows the performance results of the samples prepared in the example and Comparative Example 1 and the commercially available solvent-based intelligent repair anticorrosive coating samples of Comparative Examples 2-3 after being sprayed or brushed according to the construction process required by the detection standard, as shown in Table 1:

[0133] Table 1: Experimental effect detection data of the example and comparative examples

[0134]

[0135] From the above test results, it can be seen that the smart self-repairing water-based paint packaged by aerosol is more convenient to use, and the self-repairing range of the paint obtained after using double-coated modified graphene microcapsules is significantly improved. Through the combination of the formula, the paint has excellent weather resistance, corrosion resistance and strong adhesion to the substrate. The width of the paint automatically repaired at room temperature reaches 100-300 μm, solving the problem that the currently marketed products cannot self-repair beyond 100 μm cracking range, and solving the problem that the self-repairing conditions of the currently marketed products are harsh. The neutral salt spray resistance can reach 2000h, solving the problem that the currently marketed products have poor neutral salt spray resistance. The paint film weather resistance can reach 2000h. The paint film adhesion reaches level 1. And the water-based paint prepared according to the formula of examples 1-6 can obtain low construction loss rate and low surface drying time under the premise of meeting the environmental protection requirements, and is convenient to construct, saves time and cost, has obvious advantages compared with the comparative examples, and can effectively meet the high standard requirements of customers and market.

[0136] Comparative example 1 and example 2 are compared. Comparative example 1 uses ordinary graphene microcapsules, and the microcapsule suspension has poor storage stability during the preparation of water-based paint, which makes it difficult for the paint to stably combine with the substrate during subsequent application, and the paint film adhesion is extremely poor. Comparative examples 2-3 are ordinary smart repair coatings on the market. Although they meet most of the requirements of self-repairing water-based paint, the self-repairing width still cannot meet the high requirements of the present application, and they all have high VOC, poor environmental performance, and are harmful to the environment and human body. The above comparative examples cannot simultaneously achieve high self-repairing width while maintaining high environmental performance, high paint film adhesion and durability.

[0137] The above description is only the preferred embodiment of the present application, and is not intended to limit the present application. Any modification, equivalent replacement, improvement, etc. made within the spirit and principles of the present application shall be included in the protection scope of the present application.

Claims

1. An aerosol-type water-based self-healing coating, characterized in that, It comprises the following components in parts by weight: 10-30 parts deionized water 0.1-0.5 parts of bactericide Defoamer 0.1-0.5 parts 1-2 parts of dispersant 1-3 parts anti-settling agent Anti-flash rust agent 0.5-1 part 5-10 parts of modified zinc phosphate 5-15 parts aluminum tripolyphosphate 5-10 parts of iron oxide red or iron-titanium powder 10-35 parts of double-coated modified graphene microcapsules 20-40 parts of water-based nano fluorocarbon resin 1-5 parts of film-forming aid pH adjuster 0.1-0.5 parts 1-5 parts of propellant; The double-coated modified graphene microcapsules, by weight, comprise the following components: 30-70 parts deionized water 5-20 parts of modified graphene powder 50-70 parts of water-based silicone-modified acrylic resin 2.0wt% Ethyl methacrylate 1-5 parts 0.1-1 part urea Ammonium chloride 0.01-1 part Resorcinol 0.01-1 part 0.01-1 part of 10wt% NaOH solution 1-5 parts of octanol 50-70 parts castor oil 0.1-1 part of 30wt% formaldehyde solution; The preparation method of the double-coated modified graphene microcapsules is as follows: Mixture: Weigh 10-30 parts by weight of deionized water and modified graphene powder and put them into a container in sequence. After stirring thoroughly, add water-based organosilicon modified acrylic resin and mix evenly to form a uniformly dispersed mixture. Then filter to obtain the mixture. Emulsion: Weigh 20-40 parts by weight of deionized water and 2.0 wt% aqueous solution of ethyl methacrylate and add them sequentially to a container. While stirring at 300-400 r / min, add urea, ammonium chloride and resorcinol sequentially and mix well. Adjust the pH of the mixture to 8.5-9.0 with 10 wt% NaOH solution, add octanol dropwise, and finally add castor oil. Heat at a constant temperature to 40-50℃ and stir to emulsify for 25-30 minutes to form a uniform emulsion. Cool to room temperature to obtain the emulsion. The mixture and emulsion are mixed and stirred at 800-1000 r / min for 15-20 minutes. Then, 30wt% formaldehyde solution is added. The temperature of the mixture is raised to 55-60℃ and maintained for 3.5-4 hours to form a uniform and stable microcapsule suspension. The suspension is cooled to room temperature and then filtered to obtain double-coated modified graphene microcapsules. The modified graphene powder, by weight, comprises the following components: 20-30 parts of graphene oxide Citric acid 5-10 parts 20-30 parts of ethanol 10-20 parts of titanate coupling agent 30-50 parts of hydrazine hydrate solution.

2. The water-based self-healing coating according to claim 1, characterized in that, The titanate coupling agent is selected from at least one of monoalkoxy titanate coupling agents, chelating titanate coupling agents, and coordination titanate coupling agents.

3. The water-based self-healing coating according to claim 1, characterized in that, The double-coated modified graphene microcapsules are 15-25 parts by weight.

4. The water-based self-healing coating according to claim 1, characterized in that, The modified graphene powder is 10-15 parts by weight.

5. The water-based self-healing coating according to claim 1, characterized in that, The modified graphene powder is prepared as follows: Weigh out graphene oxide, citric acid and ethanol by weight and premix them. After dispersion, obtain graphene oxide dispersion. Add titanate coupling agent and hydrazine hydrate solution to graphene oxide dispersion and react under water bath conditions of 50-60℃. The obtained mixture was filtered and dried to obtain powdered modified graphene.

6. The method for preparing the water-based self-healing coating according to any one of claims 1-5, characterized in that, Includes the following steps: Weigh out the deionized water, bactericide, defoamer, dispersant, anti-settling agent, and anti-flash rust agent according to the weight ratio and add them to the container in sequence. Mix them evenly under low speed stirring at 300-500 r / min. Then add the modified zinc phosphate, aluminum tripolyphosphate, and iron oxide red or iron-titanium powder in sequence. Mix them evenly under medium speed stirring at 500-800 r / min and grind for more than 1 hour to make the fineness ≤30 μm. Add the ground pigment slurry to a container, then slowly add the double-coated modified graphene microcapsules, water-based nano fluorocarbon resin and film-forming aid weighed out according to the weight. Mix for 10-15 minutes at a low speed of 300-500 r / min to ensure uniform mixing. Finally, add a pH adjuster to adjust the pH value to 8.5-9.0 to obtain the water-based coating solution. The above-mentioned water-based coating liquid is filtered and filled into an aerosol can, and propellant is added according to the proportion and weight. The atomizing nozzle is then installed to produce an aerosol-type water-based self-healing coating.

7. The application of the water-based self-healing coating according to any one of claims 1-5 as a self-healing coating for metal substrates.

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