A superhydrophobic, antifouling, and self-cleaning coating and its preparation method

Abstract

This invention relates to a superhydrophobic, antifouling, and self-cleaning coating and its preparation method. The coating comprises the following components by weight: 20-50 parts fluorocarbon resin; 1-10 parts modified graphene oxide; 1-10 parts modified nano-silica; 5-15 parts curing agent; 1-5 parts dispersant; 1-5 parts leveling agent; 1-5 parts defoamer; and 30-60 parts solvent. The modified graphene oxide is obtained by modifying graphene oxide with γ-methacryloyloxypropyltrimethoxysilane. The modified nano-silica is obtained by modifying silica with octyltriethoxysilane and nonafluorohexyltriethoxysilane. Compared with the prior art, the coating obtained by this invention has excellent adhesion, superhydrophobicity, strong cleaning ability, and is not prone to pollution. It also exhibits excellent acid resistance, alkali resistance, and salt spray resistance, and can be applied to buildings, cross-sea bridges, ships, and other places that are subject to long-term rain erosion and seawater corrosion.

Description

Technical Field

[0001] This invention relates to the field of coating technology, and in particular to a superhydrophobic, antifouling, and self-cleaning coating and its preparation method. Background Technology

[0002] Fluorocarbon coatings refer to coatings that use fluoropolymers as the main film-forming substance; they are also known as fluorocarbon paints, fluoropolymer coatings, fluoropolymer coatings, etc. Among various coatings, fluoropolymer coatings possess particularly superior properties due to the high electronegativity of the introduced fluorine element and the strong carbon-fluorine bond energy. These properties include weather resistance, heat resistance, low-temperature resistance, and chemical resistance, as well as unique non-stick and low-friction properties.

[0003] As the requirements for building lifespan become increasingly stringent, the water resistance, pollution resistance, and salt spray resistance of coatings on building surfaces that are frequently exposed to rainwater, such as the seawater corrosion parts of cross-sea bridges and ships, still need to be improved.

[0004] For example, CN100554343C discloses a nano-titanium dioxide modified fluorocarbon coating and its preparation process and application. This coating is made by adding a mixture of anatase nano-TiO2 and rutile nano-TiO2 to an existing fluorocarbon coating. The addition ratio is: the weight ratio of the anatase nano-TiO2 and rutile nano-TiO2 mixture to the fluorocarbon coating is 1-4:100; in the anatase nano-TiO2 and rutile nano-TiO2 mixture, the weight ratio of anatase nano-TiO2 and rutile nano-TiO2 is 4:1.

[0005] For example, CN113637368B discloses a fluorocarbon coating, its preparation method, and its application, belonging to the field of coating preparation technology. This fluorocarbon coating is prepared by mixing component A and component B in a mass ratio of 10:(0.8-1); component A includes 60-65 parts of fluorocarbon resin, 5-10 parts of modified whisker zinc oxide, 5-10 parts of modified nano-silica, 0.3-0.5 parts of zinc molybdate, 4-8 parts of zinc borate, 0.3-0.5 parts of zinc sulfate, 0.5-1.8 parts of dispersant, 0.2-0.5 parts of leveling agent, 0.1-0.3 parts of defoamer, and 12-14 parts of solvent.

[0006] However, the aforementioned patents all involve simply adding nanoparticles to fillers to improve the roughness of the coating and thus improve its hydrophobic properties, without considering issues such as the dispersibility of nanoparticles. Therefore, this invention is proposed. Summary of the Invention

[0007] The purpose of this invention is to overcome the shortcomings of the prior art in terms of weak hydrophobic properties of coatings and to provide a superhydrophobic, antifouling, and self-cleaning coating and its preparation method.

[0008] In existing technologies, improving the hydrophobicity of fluorocarbon coatings generally involves adding hydrophobic additives such as silane coupling agents, or utilizing the roughness of nanoparticles to improve hydrophobicity. However, simply adding additives has limited effect on improving hydrophobic performance, and the addition of nanoparticles also requires consideration of issues such as dispersibility.

[0009] Therefore, the first aspect of the present invention provides a superhydrophobic, antifouling, and self-cleaning coating, comprising the following components in parts by weight:

[0010]

[0011] The modified graphene oxide was prepared by modifying graphene oxide with γ-methacryloxypropyltrimethoxysilane.

[0012] The modified nano-silica was prepared by modifying silica with octyltriethoxysilane and nonafluorohexyltriethoxysilane.

[0013] Preferably, the modified graphene oxide is prepared by the following steps:

[0014] Modified graphene oxide was obtained by mixing graphene oxide, γ-methacryloxypropyltrimethoxysilane, and an aqueous ethanol solution, stirring, and filtering.

[0015] Preferably, the mass ratio of the graphene oxide, γ-methacryloxypropyltrimethoxysilane and the aqueous ethanol solution is 1:(1-5):(100-300).

[0016] Preferably, the mass ratio of the graphene oxide, γ-methacryloxypropyltrimethoxysilane, and the aqueous ethanol solution is 1:2:200.

[0017] Preferably, the mass ratio of anhydrous ethanol to water in the ethanol-water solution is 1:1.

[0018] Preferably, the specific conditions for stirring are as follows:

[0019] Stir at 400-800 rpm for 4-8 hours at 50-80℃.

[0020] Preferably, the specific conditions for stirring are as follows:

[0021] Stir at 600 rpm for 6 hours at 60°C.

[0022] Preferably, the modified nano-silica is prepared by the following steps:

[0023] Octyltriethoxysilane and nonafluorohexyltriethoxysilane were dissolved in ethanol, the pH was adjusted to 4-6, and the mixture was stirred to carry out a first reaction to obtain a liquid phase. Then, silica was dispersed in ethanol and added to the liquid phase, the pH was adjusted to 10-12, and the mixture was stirred to carry out a second reaction. After centrifugation, washing and drying, modified nano silica was obtained.

[0024] Preferably, the mass ratio of octyltriethoxysilane, nonafluorohexyltriethoxysilane, and silicon dioxide is 1:1:(4-8).

[0025] Preferably, the mass ratio of octyltriethoxysilane, nonafluorohexyltriethoxysilane, and silicon dioxide is 1:1:6.

[0026] Preferably, the reaction time is 30-40 minutes and the temperature is 20-40°C.

[0027] Preferably, the reaction time is 35 minutes and the temperature is 30°C.

[0028] Preferably, acetic acid is used as the reagent to adjust the pH to 4-6, and ammonium hydroxide is used as the solvent to adjust the pH to 10-12.

[0029] Preferably, the secondary reaction takes 18-36 hours and is carried out at a temperature of 20-40°C.

[0030] Preferably, the secondary reaction takes 24 hours and is carried out at a temperature of 30°C.

[0031] Preferably, the fluorocarbon resin is one or more of HLR-6, ​​HLR-7, HLR-670, ZHM-2, ZHM-5, and ZHM-70.

[0032] Preferably, the fluorocarbon resin is HLR-6.

[0033] Preferably, the curing agent is one or more of aliphatic polyisocyanate, toluene diisocyanate, and diphenylmethane diisocyanate.

[0034] Preferably, the curing agent is an aliphatic polyisocyanate.

[0035] Preferably, the dispersant is one or more of BYK-110, BYK-161, Nuosperse FX600, SDA120, SDA-150, and SDA-170.

[0036] Preferably, the leveling agent is one or more of EFKA-3777, HY-3777, FC-4430, and AKN-1377.

[0037] Preferably, the defoamer is a high-carbon alcohol defoamer or an organosilicon defoamer.

[0038] Preferably, the solvent is one or more of xylene, butyl acetate, propylene glycol methyl ether acetate, and ethylene glycol ethyl ether acetate.

[0039] A second aspect of this invention provides a method for preparing a superhydrophobic, antifouling, self-cleaning coating, comprising the following steps:

[0040] S1, modified graphene oxide is obtained by mixing graphene oxide, γ-methacryloxypropyltrimethoxysilane and an aqueous ethanol solution evenly, stirring and filtering.

[0041] S2, octyltriethoxysilane and nonafluorohexyltriethoxysilane are dissolved in ethanol, the pH is adjusted to 4-6, and the mixture is stirred to carry out a first reaction to obtain a liquid phase. Then, silica is dispersed in ethanol and added to the liquid phase, the pH is adjusted to 10-12, and the mixture is stirred to carry out a second reaction. After centrifugation, washing and drying, modified nano silica is obtained.

[0042] S3. Mix 20-50 parts of fluorocarbon resin and 30-60 parts of solvent evenly. Then, while stirring, add 5-15 parts of curing agent, 1-5 parts of dispersant, 1-5 parts of leveling agent, 1-5 parts of defoamer, 1-10 parts of modified graphene oxide and 1-10 parts of modified nano silica, and mix evenly to obtain a superhydrophobic, antifouling, and self-cleaning coating.

[0043] Preferably, in step S1, the mass ratio of the graphene oxide, γ-methacryloxypropyltrimethoxysilane and the aqueous ethanol solution is 1:(1-5):(100-300).

[0044] Preferably, in step S1, the mass ratio of graphene oxide, γ-methacryloxypropyltrimethoxysilane, and aqueous ethanol solution is 1:2:200.

[0045] Preferably, in step S1, the mass ratio of anhydrous ethanol to water in the ethanol-water solution is 1:1.

[0046] Preferably, in step S1, the specific conditions for stirring are as follows:

[0047] Stir at 400-800 rpm for 4-8 hours at 50-80℃.

[0048] Preferably, in step S1, the specific conditions for stirring are as follows:

[0049] Stir at 600 rpm for 6 hours at 60°C.

[0050] Preferably, in step S2, the mass ratio of octyltriethoxysilane, nonafluorohexyltriethoxysilane, and silicon dioxide is 1:1:(4-8).

[0051] Preferably, in step S2, the mass ratio of octyltriethoxysilane, nonafluorohexyltriethoxysilane, and silicon dioxide is 1:1:6.

[0052] Preferably, in step S2, the reaction time is 30-40 minutes and the temperature is 20-40°C.

[0053] Preferably, in step S2, the reaction time is 35 minutes and the temperature is 30°C.

[0054] Preferably, in step S2, the reagent used to adjust the pH to 4-6 is acetic acid, and the solvent used to adjust the pH to 10-12 is ammonium hydroxide.

[0055] Preferably, in step S2, the secondary reaction takes 18-36 hours and the temperature is 20-40°C.

[0056] Preferably, in step S2, the secondary reaction takes 24 hours and is carried out at a temperature of 30°C.

[0057] Preferably, in step S3, the fluorocarbon resin is one or more of HLR-6, ​​HLR-7, HLR-670, ZHM-2, ZHM-5, and ZHM-70.

[0058] Preferably, in step S3, the fluorocarbon resin is HLR-6.

[0059] Preferably, in step S3, the curing agent is one or more of aliphatic polyisocyanate, toluene diisocyanate, and diphenylmethane diisocyanate.

[0060] Preferably, in step S3, the curing agent is an aliphatic polyisocyanate.

[0061] Preferably, in step S3, the dispersant is one or more of BYK-110, BYK-161, Nuosperse FX600, SDA120, SDA-150, and SDA-170.

[0062] Preferably, in step S3, the leveling agent is one or more of EFKA-3777, HY-3777, FC-4430, and AKN-1377.

[0063] Preferably, in step S3, the defoamer is a high-carbon alcohol defoamer or an organosilicon defoamer.

[0064] Preferably, in step S3, the solvent is one or more of xylene, butyl acetate, propylene glycol methyl ether acetate, and ethylene glycol ethyl ether acetate.

[0065] Compared with the prior art, the present invention has the following beneficial effects:

[0066] 1. Compared with existing methods, in this invention, the trimethoxysilane at one end of γ-methacryloxypropyltrimethoxysilane can hydrolyze to form silanol groups, which undergo condensation reactions with oxygen-containing functional groups such as hydroxyl and carboxyl groups on the surface of graphene oxide, thereby firmly grafting it onto the surface of graphene oxide to modify it. The methacryloxy group at the other end is a reactive unsaturated double bond group that can chemically react with the unsaturated double bonds in the polymer matrix (fluorocarbon resin) to form chemical bonds between graphene oxide and the polymer matrix, greatly improving the interfacial bonding force between the two. This allows the modified graphene oxide to be uniformly dispersed in the polymer matrix. Furthermore, after γ-methacryloxypropyltrimethoxysilane modifies graphene oxide, its nonpolar organic groups increase the hydrophobicity of graphene oxide, improving its solubility in organic solvents and making it easier to disperse uniformly in the polymer matrix, avoiding agglomeration. This is beneficial for preparing composite materials with uniform and stable performance, and also enhances the hydrophobicity of the resulting coating. Furthermore, graphene oxide has a sheet-like structure that can form a dense barrier layer in coatings, preventing corrosive media such as oxygen, water, and chloride ions from penetrating to the surface of the coated object, thereby slowing down the corrosion process of substrates such as metals. This physical barrier effect can significantly improve the anti-corrosion ability of coatings and extend the service life of the protected materials.

[0067] 2. Compared with existing technologies, the nonafluorohexyltriethoxysilane in this invention possesses specific fluorinated and ethoxy groups, which can react with the hydroxyl groups on the surface of silica to form chemical bonds. Through this chemical reaction, the ethoxy groups of nonafluorohexyltriethoxysilane undergo a condensation reaction with the hydroxyl groups on the silica surface, introducing fluorinated groups onto the silica surface, thereby reducing its surface energy and giving it superhydrophobic properties. Simultaneously, octyltriethoxysilane has a relatively long carbon chain structure, and its hydrolysis and condensation reaction conditions are mild. It hydrolyzes into a silanol monomer, and the silanol monomer's hydroxyl groups undergo dehydration condensation with the silanol groups on the silica nanoparticle surface to form Si-O-Si bonds, thus grafting onto the surface of the silica nanoparticles, constructing a rough surface structure, forming a dense network structure, altering its hydrophilicity, and achieving the effect of hydrophobic modification. Furthermore, due to the formation of Si-O-Si bonds, the silica nanoparticles carry a positive charge, while the γ-methacryloyloxypropyltrimethoxysilane-modified graphene oxide carries a negative charge. The two are adsorbed together through electrostatic attraction, and the methacryloyloxy groups on the modified graphene oxide can form covalent bonds with the Si-O-Si bonds, further enhancing the bonding force between the modified silica nanoparticles and the modified graphene oxide. In addition, because the modified graphene oxide is uniformly dispersed within the polymer matrix, both it and the adsorbed modified silica nanoparticles are also completely dispersed within the polymer matrix.

[0068] Furthermore, the combination of the sheet-like structure of graphene oxide and the dense network structure on the surface of modified nano-silica forms a three-dimensional network-sheet composite structure, which further prevents the entry of substances such as water, oxygen, and ions.

[0069] Therefore, nonafluorohexyltriethoxysilane and octyltriethoxysilane achieve the superhydrophobicity of the coating by reducing the surface energy of silica particles and constructing a rough surface structure, respectively, which in turn gives silica excellent hydrophobic properties. The excellent hydrophobic properties of modified graphene oxide are also present, which together achieve the superhydrophobicity of the coating formed by the coating. Detailed Implementation

[0070] To facilitate understanding of this application, it will be described more fully below through embodiments. However, this application can be implemented in many different forms and is not limited to the embodiments described herein. Rather, these embodiments are provided to provide a more thorough and complete understanding of the disclosure of this application.

[0071] For simplicity, this application only explicitly discloses some numerical ranges. However, any lower limit can be combined with any upper limit to form a range not explicitly stated; and any lower limit can be combined with other lower limits to form a range not explicitly stated, just as any upper limit can be combined with any other upper limit to form a range not explicitly stated. Furthermore, although not explicitly stated, every point or individual value between the endpoints of the range is included within that range. Therefore, each point or individual value can be used as its own lower or upper limit and combined with any other point or individual value or with other lower or upper limits to form a range not explicitly stated.

[0072] Unless otherwise defined, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this application belongs. The terminology used herein in the specification of this application is for the purpose of describing particular embodiments only and is not intended to be limiting of the application. It should be noted that, unless otherwise stated, the term "and / or" as used herein includes any and all combinations of one or more of the associated listed items, "above," "below," includes the stated number, and "one or more" with "multiple" means two or more.

[0073] In existing technologies, improving the hydrophobicity of fluorocarbon coatings generally involves adding hydrophobic additives such as silane coupling agents, or utilizing the roughness of nanoparticles to improve hydrophobicity. However, simply adding additives has limited effect on improving hydrophobic performance, and the addition of nanoparticles also requires consideration of issues such as dispersibility.

[0074] Therefore, in an optional embodiment of the present invention, a superhydrophobic, antifouling, and self-cleaning coating is provided, comprising the following components by weight:

[0075]

[0076] The modified graphene oxide was prepared by modifying graphene oxide with γ-methacryloxypropyltrimethoxysilane.

[0077] The modified nano-silica was prepared by modifying silica with octyltriethoxysilane and nonafluorohexyltriethoxysilane.

[0078] In an optional embodiment, the modified graphene oxide is prepared by the following steps:

[0079] Modified graphene oxide was obtained by mixing graphene oxide, γ-methacryloxypropyltrimethoxysilane, and an aqueous ethanol solution, stirring, and filtering.

[0080] In an optional embodiment, the mass ratio of the graphene oxide, γ-methacryloxypropyltrimethoxysilane and the aqueous ethanol solution is 1:(1-5):(100-300).

[0081] In an optional embodiment, the mass ratio of the graphene oxide, γ-methacryloxypropyltrimethoxysilane, and the aqueous ethanol solution is 1:2:200.

[0082] In an optional embodiment, the mass ratio of anhydrous ethanol to water in the ethanol-water solution is 1:1.

[0083] In an optional implementation, the specific conditions for stirring are as follows:

[0084] Stir at 400-800 rpm for 4-8 hours at 50-80℃.

[0085] In an optional implementation, the specific conditions for stirring are as follows:

[0086] Stir at 600 rpm for 6 hours at 60°C.

[0087] In some embodiments of the present invention, the trimethoxysilane at one end of γ-methacryloxypropyltrimethoxysilane can be hydrolyzed to form silanol groups, which undergo condensation reactions with oxygen-containing functional groups such as hydroxyl and carboxyl groups on the surface of graphene oxide, thereby firmly grafting onto the surface of graphene oxide to modify it. The methacryloxy group at the other end is a reactive unsaturated double bond group that can chemically react with the unsaturated double bonds in the polymer matrix (fluorocarbon resin) to form chemical bonds between graphene oxide and the polymer matrix, greatly improving the interfacial bonding force between the two. This allows the modified graphene oxide to be uniformly dispersed in the polymer matrix. Furthermore, after γ-methacryloxypropyltrimethoxysilane modifies graphene oxide, its nonpolar organic groups increase the hydrophobicity of graphene oxide, improving its solubility in organic solvents and making it easier to disperse uniformly in the polymer matrix, avoiding agglomeration and facilitating the preparation of composite materials with uniform and stable properties.

[0088] In an optional embodiment, the modified nano-silica is prepared by the following steps:

[0089] Octyltriethoxysilane and nonafluorohexyltriethoxysilane were dissolved in ethanol, the pH was adjusted to 4-6, and the mixture was stirred to carry out a first reaction to obtain a liquid phase. Then, silica was dispersed in ethanol and added to the liquid phase, the pH was adjusted to 10-12, and the mixture was stirred to carry out a second reaction. After centrifugation, washing and drying, modified nano silica was obtained.

[0090] In an optional embodiment, the mass ratio of octyltriethoxysilane, nonafluorohexyltriethoxysilane, and silicon dioxide is 1:1:(4-8).

[0091] In an optional embodiment, the mass ratio of octyltriethoxysilane, nonafluorohexyltriethoxysilane, and silicon dioxide is 1:1:6.

[0092] In an optional embodiment, the reaction time is 30-40 minutes and the temperature is 20-40°C.

[0093] In an optional embodiment, the reaction time is 35 minutes and the temperature is 30°C.

[0094] In an optional embodiment, acetic acid is used to adjust the pH to 4-6, and ammonium hydroxide is used to adjust the pH to 10-12.

[0095] In an optional embodiment, the secondary reaction takes 18-36 hours and is carried out at a temperature of 20-40°C.

[0096] In an optional embodiment, the secondary reaction takes 24 hours and is carried out at a temperature of 30°C.

[0097] In some embodiments of the present invention, nonafluorohexyltriethoxysilane has specific fluorinated and ethoxy groups, which can react with hydroxyl groups on the surface of silica to form chemical bonds. Through chemical reaction, the ethoxy groups of nonafluorohexyltriethoxysilane undergo a condensation reaction with the hydroxyl groups on the silica surface, introducing fluorinated groups onto the silica surface, thereby reducing its surface energy and giving it superhydrophobic properties. Simultaneously, octyltriethoxysilane has a relatively long carbon chain structure, and its hydrolysis and condensation reaction conditions are mild. It hydrolyzes into a silanol monomer, and the silanol monomer's hydroxyl groups undergo dehydration condensation with the silanol groups on the silica nanoparticle surface to form Si-O-Si bonds, thereby grafting onto the surface of the silica nanoparticles, constructing a rough surface structure, changing its hydrophilicity, and achieving the effect of hydrophobic modification. Furthermore, due to the formation of Si-O-Si bonds, the silica nanoparticles carry a positive charge, while the γ-methacryloyloxypropyltrimethoxysilane-modified graphene oxide carries a negative charge. The two are adsorbed together through electrostatic attraction, and the methacryloyloxy groups on the modified graphene oxide can form covalent bonds with the Si-O-Si bonds, further enhancing the bonding force between the modified silica nanoparticles and the modified graphene oxide. In addition, because the modified graphene oxide is uniformly dispersed within the polymer matrix, both it and the adsorbed modified silica nanoparticles are also completely dispersed within the polymer matrix.

[0098] Therefore, nonafluorohexyltriethoxysilane and octyltriethoxysilane achieve the superhydrophobicity of the coating by reducing the surface energy of silica particles and constructing a rough surface structure, respectively, which in turn gives silica excellent hydrophobic properties. The excellent hydrophobic properties of modified graphene oxide are also present, which together achieve the superhydrophobicity of the coating formed by the coating.

[0099] In an optional embodiment, the fluorocarbon resin is one or more of HLR-6, ​​HLR-7, HLR-670, ZHM-2, ZHM-5, and ZHM-70.

[0100] In an optional embodiment, the fluorocarbon resin is HLR-6.

[0101] In an optional embodiment, the curing agent is one or more of aliphatic polyisocyanate, toluene diisocyanate, and diphenylmethane diisocyanate.

[0102] In an optional embodiment, the curing agent is an aliphatic polyisocyanate.

[0103] In an optional embodiment, the dispersant is one or more of BYK-110, BYK-161, Nuosperse FX600, SDA120, SDA-150, and SDA-170.

[0104] In an optional embodiment, the leveling agent is one or more of EFKA-3777, HY-3777, FC-4430, and AKN-1377.

[0105] In an optional embodiment, the defoamer is a high-carbon alcohol defoamer or an organosilicone defoamer.

[0106] In an optional embodiment, the solvent is one or more of xylene, butyl acetate, propylene glycol methyl ether acetate, and ethylene glycol ethyl ether acetate.

[0107] An optional embodiment of the present invention also provides a method for preparing a superhydrophobic, antifouling, and self-cleaning coating, comprising the following steps:

[0108] S1, modified graphene oxide is obtained by mixing graphene oxide, γ-methacryloxypropyltrimethoxysilane and an aqueous ethanol solution evenly, stirring and filtering.

[0109] S2, octyltriethoxysilane and nonafluorohexyltriethoxysilane are dissolved in ethanol, the pH is adjusted to 4-6, and the mixture is stirred to carry out a first reaction to obtain a liquid phase. Then, silica is dispersed in ethanol and added to the liquid phase, the pH is adjusted to 10-12, and the mixture is stirred to carry out a second reaction. After centrifugation, washing and drying, modified nano silica is obtained.

[0110] S3. Mix 20-50 parts of fluorocarbon resin and 30-60 parts of solvent evenly. Then, while stirring, add 5-15 parts of curing agent, 1-5 parts of dispersant, 1-5 parts of leveling agent, 1-5 parts of defoamer, 1-10 parts of modified graphene oxide and 1-10 parts of modified nano silica, and mix evenly to obtain a superhydrophobic, antifouling, and self-cleaning coating.

[0111] In an optional embodiment, in step S1, the mass ratio of the graphene oxide, γ-methacryloxypropyltrimethoxysilane and the aqueous ethanol solution is 1:(1-5):(100-300).

[0112] In an optional embodiment, in step S1, the mass ratio of the graphene oxide, γ-methacryloxypropyltrimethoxysilane, and the aqueous ethanol solution is 1:2:200.

[0113] In an optional embodiment, in step S1, the mass ratio of anhydrous ethanol to water in the ethanol-water solution is 1:1.

[0114] In an optional implementation, the specific conditions for stirring in step S1 are as follows:

[0115] Stir at 400-800 rpm for 4-8 hours at 50-80℃.

[0116] In an optional implementation, the specific conditions for stirring in step S1 are as follows:

[0117] Stir at 600 rpm for 6 hours at 60°C.

[0118] In an optional embodiment, in step S2, the mass ratio of octyltriethoxysilane, nonafluorohexyltriethoxysilane, and silicon dioxide is 1:1:(4-8).

[0119] In an optional embodiment, in step S2, the mass ratio of octyltriethoxysilane, nonafluorohexyltriethoxysilane, and silicon dioxide is 1:1:6.

[0120] In an optional embodiment, in step S2, the reaction time is 30-40 minutes and the temperature is 20-40°C.

[0121] In an optional embodiment, in step S2, the reaction time is 35 minutes and the temperature is 30°C.

[0122] In an optional embodiment, in step S2, the reagent used to adjust the pH to 4-6 is acetic acid, and the solvent used to adjust the pH to 10-12 is ammonium hydroxide.

[0123] In an optional embodiment, in step S2, the secondary reaction takes 18-36 hours and the temperature is 20-40°C.

[0124] In an optional embodiment, in step S2, the secondary reaction takes 24 hours and is carried out at a temperature of 30°C.

[0125] In an optional embodiment, in step S3, the fluorocarbon resin is one or more of HLR-6, ​​HLR-7, HLR-670, ZHM-2, ZHM-5, and ZHM-70.

[0126] In an optional embodiment, in step S3, the fluorocarbon resin is HLR-6.

[0127] In an optional embodiment, in step S3, the curing agent is one or more of aliphatic polyisocyanate, toluene diisocyanate, and diphenylmethane diisocyanate.

[0128] In an optional embodiment, in step S3, the curing agent is an aliphatic polyisocyanate.

[0129] In an optional embodiment, in step S3, the dispersant is one or more of BYK-110, BYK-161, NuosperseFX600, SDA120, SDA-150, and SDA-170.

[0130] In an optional embodiment, in step S3, the leveling agent is one or more of EFKA-3777, HY-3777, FC-4430, and AKN-1377.

[0131] In an optional embodiment, in step S3, the defoamer is a high-carbon alcohol defoamer or an organosilicon defoamer.

[0132] In an optional embodiment, in step S3, the solvent is one or more of xylene, butyl acetate, propylene glycol methyl ether acetate, and ethylene glycol ethyl ether acetate.

[0133] The superhydrophobic, antifouling, and self-cleaning coating of the present invention will be described in more detail below with reference to specific embodiments.

[0134] Example 1

[0135] This embodiment provides a method for preparing a superhydrophobic, antifouling, and self-cleaning coating, including the following steps:

[0136] S1, 1 part graphene oxide, 2 parts γ-methacryloxypropyltrimethoxysilane, and 200 parts aqueous ethanol solution (the mass ratio of anhydrous ethanol to water is 1:1) are mixed evenly and stirred at 600 rpm for 6 hours, and then filtered to obtain modified graphene oxide.

[0137] S2, 1 part octyltriethoxysilane and 1 part nonafluorohexyltriethoxysilane were dissolved in 50 parts ethanol, the pH was adjusted to 5 with acetic acid, and the mixture was stirred at 30°C for 35 min to obtain a liquid phase. Then, 6 parts silica were dispersed in 50 parts ethanol and added to the liquid phase. The pH was adjusted to 11 with ammonium hydroxide, and the mixture was stirred at 30°C for 24 h. After centrifugation, washing and drying, modified nano silica was obtained.

[0138] S3. Mix 40 parts of fluorocarbon resin (HLR-6) and 50 parts of propylene glycol methyl ether acetate evenly. Then, while stirring, add 10 parts of toluene diisocyanate, 2 parts of dispersant (BYK-110), 2 parts of leveling agent (EFKA-3777), 2 parts of silicone defoamer, 8 parts of modified graphene oxide, and 8 parts of modified nano silica. Mix evenly to obtain a superhydrophobic, antifouling, and self-cleaning coating.

[0139] Example 2

[0140] This embodiment provides a method for preparing a superhydrophobic, antifouling, and self-cleaning coating, including the following steps:

[0141] S1, 1 part graphene oxide, 2 parts γ-methacryloxypropyltrimethoxysilane, and 200 parts aqueous ethanol solution (the mass ratio of anhydrous ethanol to water is 1:1) are mixed evenly and stirred at 600 rpm for 6 hours, and then filtered to obtain modified graphene oxide.

[0142] S2, 1 part octyltriethoxysilane and 1 part nonafluorohexyltriethoxysilane were dissolved in 50 parts ethanol, the pH was adjusted to 5 with acetic acid, and the mixture was stirred at 30°C for 35 min to obtain a liquid phase. Then, 6 parts silica were dispersed in 50 parts ethanol and added to the liquid phase. The pH was adjusted to 11 with ammonium hydroxide, and the mixture was stirred at 30°C for 24 h. After centrifugation, washing and drying, modified nano silica was obtained.

[0143] S3, mix 28 parts of fluorocarbon resin (HLR-6) and 42 parts of propylene glycol methyl ether acetate evenly, then add 8 parts of toluene diisocyanate, 1 part of dispersant (BYK-110), 1 part of leveling agent (EFKA-3777), 1 part of silicone defoamer, 4 parts of modified graphene oxide and 4 parts of modified nano silica while stirring, and mix evenly to obtain a superhydrophobic, antifouling and self-cleaning coating.

[0144] Example 3

[0145] This embodiment provides a method for preparing a superhydrophobic, antifouling, and self-cleaning coating, including the following steps:

[0146] S1, 1 part graphene oxide, 2 parts γ-methacryloxypropyltrimethoxysilane, and 200 parts aqueous ethanol solution (the mass ratio of anhydrous ethanol to water is 1:1) are mixed evenly and stirred at 600 rpm for 6 hours, and then filtered to obtain modified graphene oxide.

[0147] S2, 1 part octyltriethoxysilane and 1 part nonafluorohexyltriethoxysilane were dissolved in 50 parts ethanol, the pH was adjusted to 5 with acetic acid, and the mixture was stirred at 30°C for 35 min to obtain a liquid phase. Then, 6 parts silica were dispersed in 50 parts ethanol and added to the liquid phase. The pH was adjusted to 11 with ammonium hydroxide, and the mixture was stirred at 30°C for 24 h. After centrifugation, washing and drying, modified nano silica was obtained.

[0148] S3, mix 48 parts of fluorocarbon resin (HLR-6) and 57 parts of propylene glycol methyl ether acetate evenly, then add 14 parts of toluene diisocyanate, 3 parts of dispersant (BYK-110), 3 parts of leveling agent (EFKA-3777), 3 parts of silicone defoamer, 10 parts of modified graphene oxide and 10 parts of modified nano silica while stirring, and mix evenly to obtain a superhydrophobic, antifouling and self-cleaning coating.

[0149] Comparative Example 1

[0150] This comparative example provides a method for preparing a coating, including the following steps:

[0151] S1, 1 part graphene oxide, 2 parts γ-methacryloxypropyltrimethoxysilane, and 200 parts aqueous ethanol solution (the mass ratio of anhydrous ethanol to water is 1:1) are mixed evenly and stirred at 600 rpm for 6 hours, and then filtered to obtain modified graphene oxide.

[0152] S3. Mix 40 parts of fluorocarbon resin (HLR-6) and 50 parts of propylene glycol methyl ether acetate evenly. Then, while stirring, add 10 parts of toluene diisocyanate, 2 parts of dispersant (BYK-110), 2 parts of leveling agent (EFKA-3777), 2 parts of silicone defoamer, and 16 parts of modified graphene oxide. Mix evenly to obtain a superhydrophobic, antifouling, and self-cleaning coating.

[0153] Comparative Example 2

[0154] This comparative example provides a method for preparing a coating, including the following steps:

[0155] S1, 1 part octyltriethoxysilane and 1 part nonafluorohexyltriethoxysilane were dissolved in 50 parts ethanol, the pH was adjusted to 5 with acetic acid, and the mixture was stirred at 30°C for 35 min to obtain a liquid phase. Then, 6 parts silica were dispersed in 50 parts ethanol and added to the liquid phase. The pH was adjusted to 11 with ammonium hydroxide, and the mixture was stirred at 30°C for 24 h. After centrifugation, washing and drying, modified nano silica was obtained.

[0156] S2, mix 40 parts of fluorocarbon resin (HLR-6) and 50 parts of propylene glycol methyl ether acetate evenly, then add 10 parts of toluene diisocyanate, 2 parts of dispersant (BYK-110), 2 parts of leveling agent (EFKA-3777), 2 parts of silicone defoamer and 16 parts of modified nano silica while stirring, and mix evenly to obtain a superhydrophobic, antifouling and self-cleaning coating.

[0157] Comparative Example 3

[0158] This comparative example provides a method for preparing a coating, including the following steps:

[0159] S1, 1 part octyltriethoxysilane and 1 part nonafluorohexyltriethoxysilane were dissolved in 50 parts ethanol, the pH was adjusted to 5 with acetic acid, and the mixture was stirred at 30°C for 35 min to obtain a liquid phase. Then, 6 parts silica were dispersed in 50 parts ethanol and added to the liquid phase. The pH was adjusted to 11 with ammonium hydroxide, and the mixture was stirred at 30°C for 24 h. After centrifugation, washing and drying, modified nano silica was obtained.

[0160] S2, mix 40 parts of fluorocarbon resin (HLR-6) and 50 parts of propylene glycol methyl ether acetate evenly, then add 10 parts of toluene diisocyanate, 2 parts of dispersant (BYK-110), 2 parts of leveling agent (EFKA-3777), 2 parts of silicone defoamer, 8 parts of graphene oxide and 8 parts of modified nano silica while stirring, and mix evenly to obtain a superhydrophobic, antifouling and self-cleaning coating.

[0161] Comparative Example 4

[0162] This comparative example provides a method for preparing a coating, including the following steps:

[0163] S1, 1 part graphene oxide, 2 parts γ-methacryloxypropyltrimethoxysilane, and 200 parts aqueous ethanol solution (the mass ratio of anhydrous ethanol to water is 1:1) are mixed evenly and stirred at 600 rpm for 6 hours, and then filtered to obtain modified graphene oxide.

[0164] S3. Mix 40 parts of fluorocarbon resin (HLR-6) and 50 parts of propylene glycol methyl ether acetate evenly. Then, while stirring, add 10 parts of toluene diisocyanate, 2 parts of dispersant (BYK-110), 2 parts of leveling agent (EFKA-3777), 2 parts of silicone defoamer, 8 parts of modified graphene oxide, and 8 parts of nano silica. Mix evenly to obtain a superhydrophobic, antifouling, and self-cleaning coating.

[0165] Comparative Example 5

[0166] This comparative example provides a method for preparing a coating, including the following steps:

[0167] Mix 40 parts of fluorocarbon resin (HLR-6) and 50 parts of propylene glycol methyl ether acetate evenly. Then, while stirring, add 10 parts of toluene diisocyanate, 2 parts of dispersant (BYK-110), 2 parts of leveling agent (EFKA-3777), and 2 parts of silicone defoamer, and mix evenly to obtain a superhydrophobic, antifouling, and self-cleaning coating.

[0168] The differences between modified graphene oxide and modified nano-silica as fillers in the above embodiments and comparative examples are shown in Figure 1.

[0169] Table 1 shows the types of packing materials used in Examples 1 to 3 and Comparative Examples 1 to 5.

[0170] Example Packing material 1 Packing material 2 Example 1 Modified graphene oxide Modified nano silica Example 2 Modified graphene oxide Modified nano silica Example 3 Modified graphene oxide Modified nano silica Comparative Example 1 Modified graphene oxide none Comparative Example 2 none Modified nano silica Comparative Example 3 Graphene oxide Modified nano silica Comparative Example 4 Modified graphene oxide Nano silica Comparative Example 5 none none

[0171] Test case

[0172] Examples 1 to 3 and Comparative Examples 1 to 5 were applied to a metal substrate and cured to obtain a coating.

[0173] 1. Adhesion test

[0174] Test method: Use a blade or crisscross tool to make 100 small squares with a spacing of 1mm on the coating, reaching the metal substrate. Remove any burrs from the scratches. Cover the scratched area with adhesive tape (3M 610 or Yung-Ta) at a 45° angle along the 100-square grid. Flatten the tape to ensure there are no air bubbles between the tape and the coating. Hold both ends of the tape and quickly peel it off at a 90° angle to the test panel surface. No coating should peel off. Repeat this process three times.

[0175] 2. Water contact angle test

[0176] The contact angle is the angle θ between the tangent at the gas-liquid interface at the point where the gas, liquid, and solid phases meet and the liquid-solid interface. It is a measure of the degree of wetting. If θ < 90°, the solid surface is hydrophilic, meaning the liquid easily wets the solid. The smaller the contact angle, the more widely the water spreads on the substrate surface, and the better the cleaning properties. If θ > 90°, the solid surface is hydrophobic, meaning the liquid does not easily wet the solid and moves easily on the surface.

[0177] 3. Cleaning performance test

[0178] Apply oil stains to the surface of the coated stainless steel substrate and cure at room temperature for 10 days. Then wipe it with a cloth dampened with water and then dry it with a dry cloth. No stains on the surface are recorded as Grade 1, a small amount of stains on the surface are recorded as Grade 2, and a large amount of stains on the surface are recorded as Grade 3.

[0179] 4. Acid resistance

[0180] According to GB / T 1763-1979, soak at 23±2℃ for 120 hours, no bubbling, wrinkling and color spots, slight loss of gloss and discoloration are allowed.

[0181] 5. Alkali resistance

[0182] According to GB / T 1763-1979, soak at 23±2℃ for 720h, no bubbling, wrinkling and color spots, slight loss of gloss and discoloration are allowed.

[0183] 6. Salt spray resistance: In accordance with GB / T 1771-2007, 600h (the width of rust on one side of the scratch is ≤2mm, and there are no bubbles, rust, or peeling on the remaining plate surface 5mm away from the scratch).

[0184] The test results are shown in Table 2 below.

[0185] Table 2. Results of water resistance and contact angle tests of the coating.

[0186] Example Adhesion Contact angle Cleanliness acid resistance Alkali resistance Salt spray resistance Example 1 Level 0 159.8° Level 1 excellent excellent excellent Example 2 Level 0 156.9° Level 1 excellent excellent excellent Example 3 Level 0 162.8° Level 1 excellent excellent excellent Comparative Example 1 Level 1 75.9° Level 2 qualified qualified qualified Comparative Example 2 Level 1 90.6° Level 2 qualified qualified qualified Comparative Example 3 Level 1 100.8° Level 2 qualified qualified qualified Comparative Example 4 Level 1 84.5° Level 2 qualified qualified qualified Comparative Example 5 Level 1 68.2° Level 3 Unqualified Unqualified Unqualified

[0187] As shown in Table 1, the coating formed by the present invention has superior adhesion, superhydrophobicity, strong cleaning ability and is not prone to pollution compared with the comparative example. It also has excellent acid resistance, alkali resistance and salt spray resistance, and can be applied to buildings, cross-sea bridges, ships and other places that are subject to long-term rain erosion and seawater corrosion.

[0188] The above description of the embodiments is provided to enable those skilled in the art to understand and use the invention. It will be apparent to those skilled in the art that various modifications can be made to these embodiments, and the general principles described herein can be applied to other embodiments without inventive effort. Therefore, the present invention is not limited to the above embodiments, and any improvements and modifications made by those skilled in the art based on the disclosure of the present invention without departing from the scope of the invention should be within the protection scope of the present invention.

Claims

1. A superhydrophobic, antifouling, self-cleaning coating, characterized in that, Includes the following components by weight: 20-50 parts of fluorocarbon resin 1-10 parts of modified graphene oxide 1-10 parts of modified nano-silica 5-15 parts of curing agent 1-5 parts of dispersant 1-5 parts leveling agent 1-5 parts of defoamer Solvent 30-60 parts; The modified graphene oxide was prepared by modifying graphene oxide with γ-methacryloxypropyltrimethoxysilane. The modified nano-silica was prepared by modifying silica with octyltriethoxysilane and nonafluorohexyltriethoxysilane, and the modified nano-silica was prepared by the following steps: Octyltriethoxysilane and nonafluorohexyltriethoxysilane were dissolved in ethanol, the pH was adjusted to 4-6, and the mixture was stirred to carry out a first reaction to obtain a liquid phase. Silica was then dispersed in ethanol and added to the liquid phase. The pH was adjusted to 10-12, and the mixture was stirred to carry out a second reaction. After centrifugation, washing, and drying, modified nano-silica was obtained.

2. The superhydrophobic, antifouling, and self-cleaning coating according to claim 1, characterized in that, The modified graphene oxide is prepared by the following steps: Modified graphene oxide was obtained by mixing graphene oxide, γ-methacryloxypropyltrimethoxysilane, and an aqueous ethanol solution, stirring, and filtering.

3. The superhydrophobic, antifouling, and self-cleaning coating according to claim 2, characterized in that, The mass ratio of the graphene oxide, γ-methacryloxypropyltrimethoxysilane, and the aqueous ethanol solution is 1:(1-5):(100-300). And / or, the mass ratio of anhydrous ethanol to water in the ethanol-water solution is 1:1; And / or, the specific conditions for the stirring are: Stir at 400-800 rpm for 4-8 hours at 50-80℃.

4. The superhydrophobic, antifouling, and self-cleaning coating according to claim 1, characterized in that, The mass ratio of octyltriethoxysilane, nonafluorohexyltriethoxysilane and silicon dioxide is 1:1:(4-8); And / or, the duration of the single reaction is 30-40 min, and the temperature is 20-40℃; And / or, the reagent used to adjust the pH to 4-6 is acetic acid, and the solvent used to adjust the pH to 10-12 is ammonium hydroxide; And / or, the secondary reaction takes 18-36 hours and is carried out at a temperature of 20-40°C.

5. A superhydrophobic, antifouling, self-cleaning coating according to any one of claims 1-4, characterized in that, The fluorocarbon resin is one or more of HLR-6, ​​HLR-7, HLR-670, ZHM-2, ZHM-5, and ZHM-70; And / or, the curing agent is one or more of aliphatic polyisocyanates, toluene diisocyanate, and diphenylmethane diisocyanate; And / or, the dispersant is one or more of BYK-110, BYK-161, NuosperseFX600, SDA120, SDA-150, and SDA-170; And / or, the leveling agent is one or more of EFKA-3777, HY-3777, FC-4430, and AKN-1377; And / or, the defoamer is a high-carbon alcohol defoamer or an organosilicone defoamer; And / or, the solvent is one or more of xylene, butyl acetate, propylene glycol methyl ether acetate, and ethylene glycol ethyl ether acetate.

6. A method for preparing a superhydrophobic, antifouling, self-cleaning coating, characterized in that, The following steps are involved: S1, modified graphene oxide is obtained by mixing graphene oxide, γ-methacryloxypropyltrimethoxysilane and an aqueous ethanol solution evenly, stirring and filtering. S2, octyltriethoxysilane and nonafluorohexyltriethoxysilane are dissolved in ethanol, the pH is adjusted to 4-6, and the mixture is stirred to carry out a first reaction to obtain a liquid phase. Then, silica is dispersed in ethanol and added to the liquid phase, the pH is adjusted to 10-12, and the mixture is stirred to carry out a second reaction. After centrifugation, washing and drying, modified nano silica is obtained. S3. Mix 20-50 parts of fluorocarbon resin and 30-60 parts of solvent evenly. Then, while stirring, add 5-15 parts of curing agent, 1-5 parts of dispersant, 1-5 parts of leveling agent, 1-5 parts of defoamer, 1-10 parts of modified graphene oxide and 1-10 parts of modified nano silica, and mix evenly to obtain a superhydrophobic, antifouling, and self-cleaning coating.

7. The method for preparing a superhydrophobic, antifouling, self-cleaning coating according to claim 6, characterized in that, In step S1, the mass ratio of the graphene oxide, γ-methacryloxypropyltrimethoxysilane and the aqueous ethanol solution is 1:(1-5):(100-300); And / or, in step S1, the mass ratio of the graphene oxide, γ-methacryloxypropyltrimethoxysilane and the aqueous ethanol solution is 1:2:200; And / or, in step S1, the mass ratio of anhydrous ethanol to water in the ethanol aqueous solution is 1:1; And / or, in step S1, the specific conditions for stirring are: Stir at 400-800 rpm for 4-8 hours at 50-80℃.

8. The method for preparing a superhydrophobic, antifouling, self-cleaning coating according to claim 6, characterized in that, In step S2, the mass ratio of octyltriethoxysilane, nonafluorohexyltriethoxysilane and silicon dioxide is 1:1:(4-8); And / or, in step S2, the mass ratio of octyltriethoxysilane, nonafluorohexyltriethoxysilane and silicon dioxide is 1:1:6; And / or, in step S2, the reaction time is 30-40 min and the temperature is 20-40℃; And / or, in step S2, the reagent used to adjust the pH to 4-6 is acetic acid, and the solvent used to adjust the pH to 10-12 is ammonium hydroxide; And / or, in step S2, the secondary reaction takes 18-36 hours and is carried out at a temperature of 20-40°C.

9. The method for preparing a superhydrophobic, antifouling, self-cleaning coating according to claim 8, characterized in that, In step S3, the fluorocarbon resin is one or more of HLR-6, ​​HLR-7, HLR-670, ZHM-2, ZHM-5, and ZHM-70; And / or, in step S3, the curing agent is one or more of aliphatic polyisocyanate, toluene diisocyanate, and diphenylmethane diisocyanate; And / or, in step S3, the dispersant is one or more of BYK-110, BYK-161, NuosperseFX600, SDA120, SDA-150, and SDA-170; And / or, in step S3, the leveling agent is one or more of EFKA-3777, HY-3777, FC-4430, and AKN-1377; And / or, in step S3, the defoamer is a high-carbon alcohol defoamer or an organosilicon defoamer; And / or, in step S3, the solvent is one or more of xylene, butyl acetate, propylene glycol methyl ether acetate, and ethylene glycol ethyl ether acetate.

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