A two-component inorganic super-hydrophilic self-cleaning coating and its preparation method and application

Abstract

The present invention relates to the technical field of self-cleaning coatings, and in particular to a two-component inorganic super-hydrophilic self-cleaning coating and a preparation method and application thereof, comprising the following steps: (1) dissolving γ-aminopropyl triethoxysilane in an ethanol aqueous solution, then adding a titanium dioxide sol, stirring the reaction at 40-50°C for 2-4 hours, and obtaining a modified titanium dioxide sol; (2) taking nano-montmorillonite and dispersing it in ethanol, then adding tea polyphenols, and dispersing it under ultrasound for 0.5-1 hours to obtain a modified nano-montmorillonite suspension; (3) mixing a cerium nitrate solution with an alumina sol, then adding the modified montmorillonite suspension, and mixing evenly to obtain a composite alumina sol; (4) mixing and cross-linking the prepared modified titanium dioxide sol and the composite alumina sol to obtain a self-cleaning coating. The long-acting super-hydrophilic self-cleaning coating provided by the present invention has excellent self-cleaning ability, stable and long-acting super-hydrophilicity, wear resistance and antistatic effects.

Description

Technical Field

[0001] The invention relates to the technical field of self-cleaning coatings, and in particular to a two-component inorganic super-hydrophilic self-cleaning coating and a preparation method and application thereof. Background Art

[0002] With the rapid development of science and technology, environmental problems are becoming increasingly prominent. Industrial pollutants, domestic waste, sand and dust and other harmful substances have followed. Due to static electricity, penetration and other effects, they adhere to the surface of the material, affecting the appearance, performance and life, and also bringing difficulties to the later cleaning and maintenance. Especially with the emergence of high-rise buildings and large-area photovoltaic modules, cleaning is more difficult and the cost is also increasing. The concept of self-cleaning coating came into being, which can achieve the purpose of cleaning without human participation and only use natural conditions such as wind and rain. The research on self-cleaning technology began at home and abroad in the 1970s. After development, it has been widely used in building materials, electronic displays, photovoltaic fields, etc. According to the characteristics of the coating, it is divided into superhydrophilic or superhydrophobic. Among them, superhydrophilic coating refers to the contact angle between water droplets and the coating surface is less than 10°. The excellent spreading ability of water droplets on the coating surface allows it to penetrate under the dirt and carry the pollutants away from the coating surface under the action of gravity to achieve a self-cleaning effect.

[0003] The existing patent CN201811560082.X discloses a titanium dioxide-organic composite self-cleaning coating with high transmittance and lasting super hydrophilicity and a gentle preparation method thereof. The modified titanium dioxide is directly dispersed in an acrylate monomer, and then the titanium dioxide-organic composite coating can be obtained at room temperature by spin coating and UV curing. The titanium dioxide-organic composite coating prepared by this method has a transmittance greater than 90%, and the super hydrophilicity can be maintained for more than 6 months. It can catalytically decompose organic pollutants adsorbed on the surface of the coating under ultraviolet light. At the same time, the preparation process is carried out at room temperature and can be applied to a variety of substrates, such as glass, metal, ceramics, various synthetic resin substrates, etc. However, in the above technical scheme, only oil-based resin is used as the matrix, which is prone to aging and degradation. At the same time, the photocatalytic mechanism of titanium dioxide is relied on to remove oil organic pollutants, and the durability and self-cleaning effect of the coating are limited. Summary of the invention

[0004] In view of this, the present invention proposes a two-component inorganic super-hydrophilic self-cleaning coating and a preparation method and application thereof to solve the technical problems of poor durability and limited self-cleaning effect of the self-cleaning coating in the prior art.

[0005] The technical solution of the present invention is achieved as follows: The present invention provides a method for preparing a two-component inorganic super-hydrophilic self-cleaning coating, comprising the following steps:

[0006] (1) dissolving γ-aminopropyltriethoxysilane in an ethanol aqueous solution, then adding titanium dioxide sol, stirring and reacting at 40-50° C. for 2-4 hours to obtain a modified titanium dioxide sol;

[0007] (2) dispersing the nano-montmorillonite in ethanol, then adding tea polyphenols, and dispersing under ultrasound for 0.5-1 h to obtain a modified nano-montmorillonite suspension;

[0008] (3) adding aluminum hydroxide to the hydrochloric acid solution, stirring and aging, filtering to obtain a filtrate; continuously stirring the filtrate, and dropping ammonia water and polyethylene glycol into the filtrate, adjusting the pH value, continuing stirring, aging for 5-12 hours, to obtain an alumina sol; mixing the cerium nitrate solution with the alumina sol, and then adding the modified montmorillonite suspension, mixing evenly, to obtain a composite alumina sol;

[0009] (4) The prepared modified titanium dioxide sol and composite alumina sol are mixed, glutaraldehyde and tetraethoxysilane are added, and pre-crosslinked at room temperature for 1.5-2 hours to obtain a self-cleaning coating.

[0010] In the present invention, firstly, an organic layer is formed on the surface of titanium dioxide by γ-aminopropyltriethoxysilane to prevent agglomeration, and the introduction of amine groups provides active sites for subsequent reactions. Secondly, a composite structure is formed by modifying montmorillonite and alumina sol to enhance the mechanical strength and durability of the sol, and cerium ions are doped and introduced into the alumina sol. The introduction of cerium ions enables the coating to decompose organic pollutants more efficiently under ultraviolet light irradiation, thereby improving the self-cleaning effect. Finally, the modified titanium dioxide sol and the composite alumina sol are synergistically cross-linked through a cross-linking reaction to form a strong two-component inorganic network, thereby improving the mechanical strength and wear resistance of the coating, and the dense network structure reduces the penetration of water molecules and improves the rainproof performance of the coating; the two-component inorganic network improves the hydrophilicity of the coating by introducing polyhydroxy groups, ensuring that water droplets spread quickly and achieving a super-hydrophilic effect.

[0011] On the basis of the above technical solution, preferably, in step (1), the preparation of titanium dioxide sol comprises the following steps:

[0012] At room temperature, deionized water and nitric acid are added to an alcohol reagent, and the mixture is evenly mixed by magnetic stirring to obtain liquid A. n-butyl titanate is added to the alcohol reagent, and the mixture is evenly mixed in a closed atmosphere to obtain liquid B. Liquid B is slowly added dropwise to liquid A at room temperature. After the addition is completed, a stable titanium dioxide sol is obtained after aging.

[0013] On the basis of the above technical scheme, preferably, in step (1), the molar ratio of ethanol to n-butyl titanate is 30-50:1, the volume ratio of deionized water to nitric acid is 10-25:1, and the aging time is 1-3 days; the mass ratio of γ-aminopropyltriethoxysilane to titanium dioxide sol is 1-2:3-4.

[0014] Based on the above technical solution, preferably, in step (2), the mass ratio of nano-montmorillonite to tea polyphenols is 1-1.5:0.3-0.5.

[0015] By loading tea polyphenols on montmorillonite, not only the interlayer distance of montmorillonite is increased, but also an organic modified layer with specific functions is formed on its surface, which significantly improves the dispersibility of montmorillonite.

[0016] Based on the above technical solution, preferably, in step (3), the mass ratio of aluminum hydroxide to hydrochloric acid is 1:5-8, and the amount of polyethylene glycol added is 0.1-0.3% of the mass of the filtrate.

[0017] Based on the above technical solution, preferably, in step (3), the mass ratio of cerium nitrate solution, alumina sol and modified montmorillonite suspension is 0.1-0.3:2-3:1-1.5, and the concentration of cerium nitrate solution is 0.01-0.05 mol / L.

[0018] The introduction of cerium ions significantly enhances the photocatalytic activity of the system, which can produce more reactive oxygen species under ultraviolet light irradiation and accelerate the degradation of organic pollutants. At the same time, the synergistic effect of cerium ions and alumina network can improve the photocatalytic efficiency and thus enhance the self-cleaning effect.

[0019] On the basis of the above technical solution, preferably, in step (4), the mass ratio of the modified titanium dioxide sol to the composite alumina sol is 0.25-1.5.

[0020] Based on the above technical solution, preferably, in step (4), the amount of tetraethoxysilane added is 3-5% of the total mass of the modified titanium dioxide sol and the composite alumina sol, and the amount of glutaraldehyde added is 5-10% of the total mass of the modified titanium dioxide sol and the composite alumina sol.

[0021] During the pre-cross-linking stage at room temperature, glutaraldehyde acts as a cross-linking agent to react with the amino groups on the surface of modified titanium dioxide to form a preliminary network structure. At the same time, tetraethoxysilane builds a silicon-oxygen network in the system, forming an interpenetrating network structure with alumina and titanium dioxide. The density of the network structure enhances the waterproof performance of the coating. At the same time, the photocatalytic activity of titanium dioxide and the synergistic catalytic effect of cerium ions are maintained, ensuring the self-cleaning function of the coating.

[0022] The present invention provides a two-component inorganic super-hydrophilic self-cleaning coating prepared by the above-mentioned preparation method.

[0023] The present invention provides an application of a two-component inorganic super-hydrophilic self-cleaning coating, wherein the self-cleaning coating is used for any one of glass, PET and organic glass, and the coating method of the self-cleaning coating is any one of drip coating, spray coating, brush coating and dip-pull coating. More preferably, the coating method of the self-cleaning coating is dip-pull coating, and the pull speed is 10-200 mm / min, more preferably 10-100 mm / min; the substrate used for the self-cleaning coating is inorganic glass.

[0024] The two-component inorganic super-hydrophilic self-cleaning coating and its preparation method and application of the present invention have the following beneficial effects compared with the prior art:

[0025] (1) Through the synergistic effect of modified titanium dioxide sol and composite alumina sol, an organic-inorganic dual network structure system is constructed, which significantly improves the durability and waterproof performance of the self-cleaning coating, while maintaining the excellent photocatalytic activity of titanium dioxide and improving the self-cleaning function of the coating. Among them, the modified titanium dioxide provides active amine sites through surface modification by γ-aminopropyltriethoxysilane, and the composite alumina sol forms a stable composite network through cerium ion doping and the addition of modified montmorillonite. Under the dual cross-linking action of glutaraldehyde and tetraethoxysilane, the amine group forms a stable acetal bond with glutaraldehyde, and tetraethoxysilane constructs a continuous silicon-oxygen network, finally forming a composite coating with a dense structure and excellent performance;

[0026] (2) Under ultraviolet light, titanium dioxide can generate electron-hole pairs and generate active free radicals to decompose organic pollutants; at the same time, its abundant hydroxyl groups on the surface provide excellent hydrophilic properties, which help to form a uniform water film and promote the rapid removal of pollutants. The organic modification layer formed on the surface of titanium dioxide by γ-aminopropyltriethoxysilane not only effectively prevents the aggregation of nanoparticles and improves the dispersion stability, but also enhances the interfacial bonding force through the formation of Si-O-Ti bonds; at the same time, the introduced amino groups and other active groups provide reaction sites for subsequent cross-linking reactions, which helps to construct an organic-inorganic double network structure; in addition, the protective effect of the organic modification layer reduces self-degradation during the photocatalytic process, improves the durability of the coating, and through the synergistic effect with other components (such as aluminum oxide), the overall improvement of coating performance and the effective integration of functions are achieved.

[0027] (3) By compounding cerium nitrate with alumina sol, uniform doping of cerium ions was achieved while maintaining the supporting effect of the alumina network structure; the synergistic photocatalytic effect of cerium ions and titanium dioxide significantly improved the self-cleaning efficiency of the coating. Tea polyphenols were used to modify nano-montmorillonite. The dispersion of montmorillonite was significantly improved through the multiple effects of the rich hydroxyl groups of polyphenol compounds on the surface of montmorillonite. The modified montmorillonite not only enhanced the overall mechanical properties of the coating, but its layered structure also formed an interpenetrating network with the alumina sol. At the same time, the antioxidant properties of tea polyphenols improved the weather resistance of the coating, achieving a synergistic effect of structural enhancement and functional improvement.

[0028] (4) The preparation method of the long-lasting super-hydrophilic self-cleaning coating provided by the present invention is simple, and the coating method can be spraying, dipping and pulling, etc., which is suitable for various application environments. The coating has excellent self-cleaning ability, stable and long-lasting super-hydrophilicity, wear resistance and antistatic effects, and is suitable for various fields such as sensor cameras, glass curtain walls, solar photovoltaic panels, etc. BRIEF DESCRIPTION OF THE DRAWINGS

[0029] In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the drawings required for use in the embodiments or the description of the prior art will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying creative work.

[0030] Figure 1 The contact angles of the self-cleaning coating surface prepared in Example 1 of the present invention and the blank glass substrate surface;

[0031] Figure 2 This is a schematic diagram comparing the visible light transmittance of the self-cleaning coating and blank glass in Example 1 of the present invention;

[0032] Figure 3 It is a schematic diagram of the anti-static adsorption experiment of the coating and a test diagram of the adsorption effect of the self-cleaning coating prepared in Example 1 on the foam ball;

[0033] Figure 4 This is a self-cleaning effect test diagram of the self-cleaning coating prepared in Example 1 of the present invention;

[0034] Figure 5 This is a test diagram of the outdoor self-cleaning effect of the glass containing the self-cleaning coating prepared in Example 1 of the present invention;

[0035] Figure 6 This is a test diagram of the outdoor self-cleaning effect of the lens containing the self-cleaning coating prepared in Example 1 of the present invention. DETAILED DESCRIPTION

[0036] The following will be combined with the embodiments of the present invention to clearly and completely describe the technical solutions in the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0037] Example 1

[0038] This embodiment provides a two-component inorganic super-hydrophilic self-cleaning coating and a preparation method thereof, which specifically comprises the following steps:

[0039] (1) At room temperature, 2.0 mol of deionized water and 0.2 mol of nitric acid were added to 40 mol of anhydrous ethanol, and the mixture was stirred magnetically for 15 min to obtain liquid A; 1 mol of n-butyl titanate was added to 40 mol of ethanol, and the mixture was stirred evenly in a closed environment to obtain liquid B; at room temperature, liquid B was slowly added dropwise to liquid A, and after the addition was completed, the mixture was aged at 20° C. for 72 h to obtain a stable and uniformly dispersed titanium dioxide sol;

[0040] 15 g of γ-aminopropyltriethoxysilane was dissolved in 150 g of ethanol aqueous solution (the volume ratio of ethanol to water was 3:1), and then 35 g of titanium dioxide sol was added, and the mixture was stirred and reacted at 45° C. for 3 h to obtain a modified titanium dioxide sol.

[0041] (2) 12.5 g of nano-montmorillonite was dispersed in 200 g of ethanol, and then 4 g of tea polyphenols was added and dispersed under ultrasound at room temperature for 45 min to obtain a modified nano-montmorillonite suspension;

[0042] (3) preparing a 20% hydrochloric acid solution, slowly adding aluminum hydroxide to the hydrochloric acid at a mass ratio of 1:5, heating to 70°C and stirring for 3 hours, then aging for 12 hours, filtering to obtain a filtrate; continuously stirring the filtrate, and dripping 6% ammonia water and 0.15% polyethylene glycol by mass of the filtrate into the filtrate, maintaining the reaction temperature at 80°C, adjusting the pH value to 8-9, and continuing stirring for 30 minutes. After aging for 8 hours, an alumina sol is obtained;

[0043] 2 g of cerium nitrate solution (0.03 mol / L) was slowly added to 25 g of alumina sol and stirred for 10 min. Then, 12.5 g of modified montmorillonite suspension was added and stirred at a speed of 300 rpm for 30 min to obtain composite alumina sol.

[0044] (4) 10 g of modified titanium dioxide sol and 12.5 g of composite alumina sol were dispersed in 200 g of ethanol, 1.7 g of glutaraldehyde and 0.9 g of tetraethoxysilane were added, and pre-crosslinking was performed at room temperature for 1.8 h. The obtained sol solution was filtered through a 0.45 μm filter membrane to remove possible gel particles, thereby obtaining a self-cleaning coating.

[0045] Example 2

[0046] This embodiment provides a two-component inorganic super-hydrophilic self-cleaning coating and a preparation method thereof, which specifically comprises the following steps:

[0047] (1) At room temperature, 3.5 mol of deionized water and 0.35 mol of nitric acid were added to 40 mol of anhydrous ethanol, and the mixture was stirred magnetically for 15 min to obtain liquid A; 0.8 mol of n-butyl titanate was added to 40 mol of ethanol, and the mixture was stirred evenly in a closed environment to obtain liquid B; at room temperature, liquid B was slowly added dropwise to liquid A, and after the addition was completed, the mixture was aged at 20° C. for 72 h to obtain a stable and uniformly dispersed titanium dioxide sol;

[0048] 10 g of γ-aminopropyltriethoxysilane was dissolved in 100 g of ethanol aqueous solution (the volume ratio of ethanol to water was 3:1), and then 30 g of titanium dioxide sol was added, and the mixture was stirred and reacted at 40° C. for 4 h to obtain a modified titanium dioxide sol.

[0049] (2) 10 g of nano-montmorillonite was dispersed in 100 g of ethanol, and then 3 g of tea polyphenols was added and dispersed under ultrasound at room temperature for 0.5 h to obtain a modified nano-montmorillonite suspension;

[0050] (3) preparing a 20% hydrochloric acid solution, slowly adding aluminum hydroxide to the hydrochloric acid at a mass ratio of 1:6, heating to 80°C and stirring for 3 hours, then aging for 12 hours, filtering to obtain a filtrate; continuously stirring the filtrate, and dripping 6% ammonia water and 0.3% polyethylene glycol by mass of the filtrate into the filtrate, maintaining the reaction temperature at 90°C, adjusting the pH value to 8-9, and continuing stirring for 30 minutes. After aging for 7 hours, an alumina sol is obtained;

[0051] 1 g of cerium nitrate solution (0.01 mol / L) was slowly added to 20 g of alumina sol, stirred for 10 min, and then 10 g of modified montmorillonite suspension was added, the stirring speed was 300 rpm, and the mixture was stirred for 30 min to obtain a composite alumina sol.

[0052] (4) Disperse 10 g of modified titanium dioxide sol and 5 g of composite alumina sol in 200 g of ethanol, add 1.1 g of glutaraldehyde and 0.7 g of tetraethoxysilane, and pre-crosslink at room temperature for 1.5 h. Filter the resulting sol solution through a 0.45 μm filter membrane to remove possible gel particles, thereby obtaining a self-cleaning coating.

[0053] Example 3

[0054] This embodiment provides a two-component inorganic super-hydrophilic self-cleaning coating and a preparation method thereof, which specifically comprises the following steps:

[0055] (1) At room temperature, 3.0 mol of deionized water and 0.3 mol of nitric acid were added to 40 mol of anhydrous ethanol, and the mixture was stirred magnetically for 15 min to obtain liquid A; 1 mol of n-butyl titanate was added to 40 mol of ethanol, and the mixture was stirred evenly in a closed environment to obtain liquid B; at room temperature, liquid B was slowly added dropwise to liquid A, and after the addition was completed, the mixture was aged at 20° C. for 72 h to obtain a stable and uniformly dispersed titanium dioxide sol;

[0056] 20 g of γ-aminopropyltriethoxysilane was dissolved in 200 g of ethanol aqueous solution (the volume ratio of ethanol to water was 3:1), and then 40 g of titanium dioxide sol was added, and the mixture was stirred and reacted at 50° C. for 2 h to obtain a modified titanium dioxide sol.

[0057] (2) 15 g of nano-montmorillonite was dispersed in 200 g of ethanol, and then 5 g of tea polyphenols was added and dispersed under ultrasound at room temperature for 1 h to obtain a modified nano-montmorillonite suspension;

[0058] (3) preparing a 20% hydrochloric acid solution, slowly adding aluminum hydroxide to the hydrochloric acid at a mass ratio of 1:7, heating to 85°C and stirring for 3 hours, then aging for 12 hours, filtering to obtain a filtrate; continuously stirring the filtrate, and dripping 6% ammonia water and 0.15% polyethylene glycol by mass of the filtrate into the filtrate, maintaining the reaction temperature at 80°C, adjusting the pH value to 8-9, and continuing stirring for 30 minutes. After aging for 8 hours, an alumina sol is obtained;

[0059] 3 g of cerium nitrate solution (0.05 mol / L) was slowly added to 30 g of alumina sol and stirred for 10 min. Then, 15 g of modified montmorillonite suspension was added and stirred at a speed of 300 rpm for 30 min to obtain composite alumina sol.

[0060] (4) Disperse 10 g of modified titanium dioxide sol and 10 g of composite alumina sol in 200 g of ethanol, add 2.3 g of glutaraldehyde and 1.13 g of tetraethoxysilane, and pre-crosslink at room temperature for 2 h. Filter the resulting sol solution through a 0.45 μm filter membrane to remove possible gel particles, thereby obtaining a self-cleaning coating.

[0061] Example 4

[0062] This embodiment provides a two-component inorganic super-hydrophilic self-cleaning coating and a preparation method thereof, which specifically comprises the following steps:

[0063] (1) At room temperature, 4.0 mol of deionized water and 0.32 mol of nitric acid were added to 40 mol of anhydrous ethanol, and the mixture was stirred magnetically for 15 min to obtain liquid A; 1.5 mol of n-butyl titanate was added to 40 mol of ethanol, and the mixture was stirred evenly in a closed environment to obtain liquid B; at room temperature, liquid B was slowly added dropwise to liquid A, and after the addition was completed, the mixture was aged at 20° C. for 72 h to obtain a stable and uniformly dispersed titanium dioxide sol;

[0064] 14 g of γ-aminopropyltriethoxysilane was dissolved in 160 g of ethanol aqueous solution (the volume ratio of ethanol to water was 3:1), and then 36 g of titanium dioxide sol was added, and the mixture was stirred and reacted at 45° C. for 3.5 h to obtain a modified titanium dioxide sol.

[0065] (2) 13 g of nano-montmorillonite was dispersed in 130 g of ethanol, and then 3.5 g of tea polyphenols was added and dispersed under ultrasound at room temperature for 0.8 h to obtain a modified nano-montmorillonite suspension;

[0066] (3) preparing a 20% hydrochloric acid solution, slowly adding aluminum hydroxide to the hydrochloric acid at a mass ratio of 1:8, heating to 88°C and stirring for 3 hours, then aging for 12 hours, filtering to obtain a filtrate; continuously stirring the filtrate, and dripping 6% ammonia water and 0.22% polyethylene glycol by mass of the filtrate into the filtrate, maintaining the reaction temperature at 80°C, adjusting the pH value to 8-9, and continuing stirring for 30 minutes. After aging for 8 hours, an alumina sol is obtained;

[0067] 2.5 g of cerium nitrate solution (0.02 mol / L) was slowly added to 25 g of alumina sol and stirred for 10 min. Then, 12 g of modified montmorillonite suspension was added and stirred at a speed of 300 rpm for 30 min to obtain composite alumina sol.

[0068] (4) 10 g of modified titanium dioxide sol and 7.5 g of composite alumina sol were dispersed in 200 g of ethanol, 1.6 g of glutaraldehyde and 1.0 g of tetraethoxysilane were added, and after pre-crosslinking at room temperature for 1.6 h, the obtained sol solution was filtered through a 0.45 μm filter membrane to remove possible gel particles, thereby obtaining a self-cleaning coating.

[0069] Comparative Example 1

[0070] This comparative example provides a two-component inorganic super-hydrophilic self-cleaning coating and a preparation method thereof, which specifically comprises the following steps:

[0071] (1) At room temperature, 2.0 mol of deionized water and 0.2 mol of nitric acid were added to 40 mol of anhydrous ethanol, and the mixture was stirred magnetically for 15 min to obtain liquid A; 1 mol of n-butyl titanate was added to 40 mol of ethanol, and the mixture was stirred evenly in a closed environment to obtain liquid B; at room temperature, liquid B was slowly added dropwise to liquid A, and after the addition was completed, the mixture was aged at 20° C. for 72 h to obtain a stable and uniformly dispersed titanium dioxide sol;

[0072] (2) preparing a 20% hydrochloric acid solution, slowly adding aluminum hydroxide to the hydrochloric acid at a mass ratio of 1:5, heating to 70°C and stirring for 3 hours, then aging for 12 hours, filtering to obtain a filtrate; continuously stirring the filtrate, and dripping 6% ammonia water and 0.15% polyethylene glycol by mass of the filtrate into the filtrate, maintaining the reaction temperature at 80°C, adjusting the pH value to 8-9, and continuing stirring for 30 minutes. After aging for 8 hours, an alumina sol is obtained;

[0073] (3) Disperse 10 g of modified titanium dioxide sol and 12.5 g of composite alumina sol in 200 g of ethanol and stir for 3 h to mix them evenly. Filter the obtained sol solution through a 0.45 μm filter membrane to remove possible gel particles, thereby obtaining a self-cleaning coating.

[0074] Comparative Example 2

[0075] This comparative example provides a two-component inorganic super-hydrophilic self-cleaning coating and a preparation method thereof, which specifically comprises the following steps:

[0076] (1) At room temperature, 2.0 mol of deionized water and 0.2 mol of nitric acid were added to 40 mol of anhydrous ethanol, and the mixture was stirred magnetically for 15 min to obtain liquid A; 1 mol of n-butyl titanate was added to 40 mol of ethanol, and the mixture was stirred evenly in a closed environment to obtain liquid B; at room temperature, liquid B was slowly added dropwise to liquid A, and after the addition was completed, the mixture was aged at 20° C. for 72 h to obtain a stable and uniformly dispersed titanium dioxide sol;

[0077] (2) 12.5 g of nano-montmorillonite was dispersed in 200 g of ethanol, and then 4 g of tea polyphenols was added and dispersed under ultrasound at room temperature for 45 min to obtain a modified nano-montmorillonite suspension;

[0078] (3) preparing a 20% hydrochloric acid solution, slowly adding aluminum hydroxide to the hydrochloric acid at a mass ratio of 1:5, heating to 70°C and stirring for 3 hours, then aging for 12 hours, filtering to obtain a filtrate; continuously stirring the filtrate, and dripping 6% ammonia water and 0.15% polyethylene glycol by mass of the filtrate into the filtrate, maintaining the reaction temperature at 80°C, adjusting the pH value to 8-9, and continuing stirring for 30 minutes. After aging for 8 hours, an alumina sol is obtained;

[0079] 2 g of cerium nitrate solution (0.03 mol / L) was slowly added to 25 g of alumina sol and stirred for 10 min. Then, 12.5 g of modified montmorillonite suspension was added and stirred at a speed of 300 rpm for 30 min to obtain composite alumina sol.

[0080] (4) 10 g of titanium dioxide sol and 12.5 g of composite alumina sol were dispersed in 200 g of ethanol, 1.7 g of glutaraldehyde and 0.9 g of tetraethoxysilane were added, and pre-crosslinking was carried out at room temperature for 1.8 h. The obtained sol solution was filtered through a 0.45 μm filter membrane to remove possible gel particles, thereby obtaining a self-cleaning coating.

[0081] Comparative Example 3

[0082] This comparative example provides a two-component inorganic super-hydrophilic self-cleaning coating and a preparation method thereof, which specifically comprises the following steps:

[0083] (1) At room temperature, 2.0 mol of deionized water and 0.2 mol of nitric acid were added to 40 mol of anhydrous ethanol, and the mixture was stirred magnetically for 15 min to obtain liquid A; 1 mol of n-butyl titanate was added to 40 mol of ethanol, and the mixture was stirred evenly in a closed environment to obtain liquid B; at room temperature, liquid B was slowly added dropwise to liquid A, and after the addition was completed, the mixture was aged at 20° C. for 72 h to obtain a stable and uniformly dispersed titanium dioxide sol;

[0084] 15 g of γ-aminopropyltriethoxysilane was dissolved in 150 g of ethanol aqueous solution (the volume ratio of ethanol to water was 3:1), and then 35 g of titanium dioxide sol was added, and the mixture was stirred and reacted at 45° C. for 3 h to obtain a modified titanium dioxide sol.

[0085] (2) preparing a 20% hydrochloric acid solution, slowly adding aluminum hydroxide to the hydrochloric acid at a mass ratio of 1:5, heating to 70°C and stirring for 3 hours, then aging for 12 hours, filtering to obtain a filtrate; continuously stirring the filtrate, and dripping 6% ammonia water and 0.15% polyethylene glycol by mass of the filtrate into the filtrate, maintaining the reaction temperature at 80°C, adjusting the pH value to 8-9, and continuing stirring for 30 minutes. After aging for 8 hours, an alumina sol is obtained;

[0086] 2 g of cerium nitrate solution (0.03 mol / L) was slowly added to 25 g of alumina sol, stirred for 10 min at a stirring speed of 300 rpm, and stirred and mixed for 30 min to obtain a composite alumina sol.

[0087] (3) Disperse 10 g of modified titanium dioxide sol and 12.5 g of composite alumina sol in 200 g of ethanol, add 1.7 g of glutaraldehyde and 0.9 g of tetraethoxysilane, and pre-crosslink at room temperature for 1.8 h. Filter the resulting sol solution through a 0.45 μm filter membrane to remove possible gel particles, thereby obtaining a self-cleaning coating.

[0088] Comparative Example 4

[0089] This embodiment provides a two-component inorganic super-hydrophilic self-cleaning coating and a preparation method thereof, which specifically comprises the following steps:

[0090] (1) At room temperature, 2.0 mol of deionized water and 0.2 mol of nitric acid were added to 40 mol of anhydrous ethanol, and the mixture was stirred magnetically for 15 min to obtain liquid A; 1 mol of n-butyl titanate was added to 40 mol of ethanol, and the mixture was stirred evenly in a closed environment to obtain liquid B; at room temperature, liquid B was slowly added dropwise to liquid A, and after the addition was completed, the mixture was aged at 20° C. for 72 h to obtain a stable and uniformly dispersed titanium dioxide sol;

[0091] 15 g of γ-aminopropyltriethoxysilane was dissolved in 150 g of ethanol aqueous solution (the volume ratio of ethanol to water was 3:1), and then 35 g of titanium dioxide sol was added, and the mixture was stirred and reacted at 45° C. for 3 h to obtain a modified titanium dioxide sol.

[0092] (2) 12.5 g of nano-montmorillonite was dispersed in 200 g of ethanol, and then 4 g of tea polyphenols was added and dispersed under ultrasound at room temperature for 45 min to obtain a modified nano-montmorillonite suspension;

[0093] (3) preparing a 20% hydrochloric acid solution, slowly adding aluminum hydroxide to the hydrochloric acid at a mass ratio of 1:5, heating to 70°C and stirring for 3 hours, then aging for 12 hours, filtering to obtain a filtrate; continuously stirring the filtrate, and dripping 6% ammonia water and 0.15% polyethylene glycol by mass of the filtrate into the filtrate, maintaining the reaction temperature at 80°C, adjusting the pH value to 8-9, and continuing stirring for 30 minutes. After aging for 8 hours, an alumina sol is obtained;

[0094] 25 g of alumina sol and 12.5 g of modified montmorillonite suspension were mixed at a stirring speed of 300 rpm for 30 minutes to obtain a composite alumina sol.

[0095] (4) 10 g of modified titanium dioxide sol and 12.5 g of composite alumina sol were dispersed in 200 g of ethanol, 1.7 g of glutaraldehyde and 0.9 g of tetraethoxysilane were added, and pre-crosslinking was performed at room temperature for 1.8 h. The obtained sol solution was filtered through a 0.45 μm filter membrane to remove possible gel particles, thereby obtaining a self-cleaning coating.

[0096] Application Examples

[0097] The self-cleaning coating prepared in the examples and comparative examples was prepared by the dip-pull method, and the dip-pull coating machine was used to control the pull speed to be 20 mm / min. For the coating to be prepared by spraying, the inorganic mixed sol liquid was placed in an atomizing spray bottle and sprayed on the glass substrate at an angle of 45°. After coating, the temperature was raised to 60°C for heat treatment for 20 minutes to promote the crosslinking of the self-cleaning coating, and then cooled to room temperature.

[0098] Performance Testing

[0099] 1. The self-cleaning coating formed in the embodiment and the comparative example was subjected to hardness test, contact angle test and durability test, wherein the hardness test was conducted on the pencil hardness of the coating according to the national standard GB / T6739-1996; contact angle test: under the condition of ultraviolet light irradiation, the self-cleaning coating material was placed horizontally, and the contact angle of water at equilibrium was measured using an optical contact angle meter (OCA20); durability test: the glass with the coating was placed under the nylon wipe of the scrubber, a weight of 1KG was applied, and deionized water containing a surfactant was added at a speed of 1.5mL / min, and the coating was subjected to durability test according to the set number of cycles. The test results are shown in Table 1.

[0100] Table 1 Hardness and contact angle test results

[0101]

[0102]

[0103] It can be seen from Table 1 that the self-cleaning coating prepared by the technical solution of the embodiment of the present invention has good hardness and super hydrophilicity, and good durability.

[0104] Figure 1 The contact angles of the blank glass substrate surface and the self-cleaning coating surface prepared in Example 1 are shown. Figure 1 a is the contact angle of the blank glass surface, Figure 1 b is the contact angle of the self-cleaning coating surface. It can be seen from the figure that the contact angle of the coating surface prepared in Example 1 is 7°, and the contact angle of the blank glass surface is 18°.

[0105] 2. The self-cleaning coatings formed in the embodiments and comparative examples were tested for light transmittance and self-cleaning effect, wherein the light transmittance was tested using a haze meter for the self-cleaning coating or blank glass for visible light with a wavelength in the range of 400-700nm. The higher the light transmittance, the better the transparency of the coating. Self-cleaning effect test: blank glass and glass with self-cleaning coating were placed on the roof outdoor platform at the same inclination angle, and the cleanliness of the surface was observed after 1 month and 3 months, respectively, and the light transmittance was tested to determine the self-cleaning effect of the coating. The test results are shown in Table 2.

[0106] Table 2 Transmittance and self-cleaning effect test

[0107]

[0108]

[0109] It can be seen from Table 2 that the self-cleaning coating prepared by the technical solution of the embodiment of the present invention has little effect on the light transmittance of the blank glass and has a good self-cleaning effect.

[0110] Figure 2 A schematic diagram comparing the visible light transmittance of the self-cleaning coating of Example 1 and blank glass is shown. As can be seen from the figure, the self-cleaning coating has little effect on the light transmittance of the blank glass.

[0111] Figure 3 The schematic diagram of the coating antistatic adsorption experiment and the adsorption effect of the self-cleaning coating prepared in Example 1 of the present invention on the foam ball are shown. Figure 3 a is a schematic diagram of the coating antistatic adsorption experiment. Figure 3 b is a diagram showing the adsorption effect of the self-cleaning coating on foam balls prepared in Example 1. The PET film coated with the self-cleaning coating on the right side was attached to the glass, and a force of about 1N was applied. After 30 cycles of reciprocating friction with the PTFE film at a constant speed, a polystyrene foam ball was suspended above it. The untreated PET film surface on the left side adsorbed more foam balls, while the modified PET film surface on the right side had no foam balls adsorbed.

[0112] Figure 4 The self-cleaning effect of the self-cleaning coating prepared in Example 1 of the present invention is shown. Dust is sprinkled on the surface of a blank lens and a lens coated with the self-cleaning coating of Example 1, and a few drops of clean water are dripped on the top of the lens. It can be seen that the surface of the treated lens becomes clean due to its super hydrophilic self-cleaning effect. Water droplets flow down the surface of the blank lens in streams, and dust is still attached to the lens surface.

[0113] like Figure 5As shown, after the glass coated with Example 1 on the left and blank untreated on the right were exposed to the outdoor environment for one month, stains adhered to the surfaces of both sides of the glass. When water was evenly sprayed on the surface, it was found that the treated glass surface on the left immediately became clean and moistened, while the blank glass surface on the right was not moistened by water droplets and stains remained.

[0114] The coating was applied to the surface of the sensor lens by spraying, and a blank lens was selected as a control. Figure 6 It can be seen that after the surface of the sensor lens coated with the sol coating is completely dried, a uniform diffraction pattern is formed ( Figure 6 a, 6b). In order to verify its outdoor self-cleaning and anti-fouling performance, the surface morphology of the sensor lens was recorded in real time after the rain. It can be observed that after being placed outdoors for 30 days, a lot of dust adhered to the surface of the blank sensor lens without coating ( Figure 6 c) For the sensor lens coated with self-cleaning coating, due to its self-cleaning performance, rainwater will wash away the dust on the surface, and the surface will remain clean ( Figure 6 d).

[0115] The above description is only a preferred embodiment of the present invention and is not intended to limit the present invention. Any modifications, equivalent substitutions, improvements, etc. made within the spirit and principles of the present invention should be included in the protection scope of the present invention.

Claims

1. A method for preparing a two-component inorganic super-hydrophilic self-cleaning coating, characterized in that: The following steps are involved: (1) Dissolving γ-aminopropyltriethoxysilane in an ethanol aqueous solution, then adding titanium dioxide sol, stirring and reacting at 40-50° C. for 2-4 hours to obtain a modified titanium dioxide sol; (2) Dispersing nano-montmorillonite in ethanol, then adding tea polyphenols, and dispersing under ultrasound for 0.5-1h to obtain a modified nano-montmorillonite suspension; (3) adding aluminum hydroxide to the hydrochloric acid solution, stirring and aging, filtering to obtain a filtrate; continuously stirring the filtrate, and dropping ammonia water and polyethylene glycol into the filtrate, adjusting the pH value, continuing stirring, aging for 5-12 hours, and obtaining an alumina sol; The cerium nitrate solution is mixed with the alumina sol, and then the modified nano-montmorillonite suspension is added and mixed evenly to obtain a composite alumina sol; (4) The prepared modified titanium dioxide sol and composite alumina sol are mixed, glutaraldehyde and tetraethoxysilane are added, and pre-crosslinked at room temperature for 1.5-2 hours to obtain a self-cleaning coating.

2. The method for preparing a two-component inorganic super-hydrophilic self-cleaning coating according to claim 1, characterized in that: In step (1), the preparation of titanium dioxide sol comprises the following steps: At room temperature, deionized water and nitric acid are added to anhydrous ethanol, and the mixture is evenly mixed by magnetic stirring to obtain liquid A. n-butyl titanate is added to ethanol, and the mixture is evenly mixed in a closed atmosphere to obtain liquid B. Liquid B is slowly added dropwise to liquid A at room temperature. After the addition is completed, a stable titanium dioxide sol is obtained after aging.

3. The method for preparing a two-component inorganic super-hydrophilic self-cleaning coating according to claim 2, characterized in that: In step (1), the volume ratio of deionized water to nitric acid is 10-25:1, and the aging time is 1-3 days; the mass ratio of γ-aminopropyltriethoxysilane to titanium dioxide sol is 1-2:3-4.

4. The method for preparing a two-component inorganic super-hydrophilic self-cleaning coating according to claim 1, characterized in that: In step (2), the mass ratio of nano-montmorillonite to tea polyphenols is 1-1.5:0.3-0.

5.

5. The method for preparing a two-component inorganic super-hydrophilic self-cleaning coating according to claim 1, characterized in that: In step (3), the mass ratio of aluminum hydroxide to hydrochloric acid is 1:5-8, and the amount of polyethylene glycol added is 0.1-0.3% of the mass of the filtrate.

6. The method for preparing a two-component inorganic super-hydrophilic self-cleaning coating according to claim 1, characterized in that: In step (3), the mass ratio of the cerium nitrate solution, the alumina sol and the modified nano-montmorillonite suspension is 0.1-0.3:2-3:1-1.5, and the concentration of the cerium nitrate solution is 0.01-0.05 mol / L.

7. The method for preparing a two-component inorganic super-hydrophilic self-cleaning coating according to claim 1, characterized in that: In step (4), the mass ratio of the modified titanium dioxide sol to the composite alumina sol is 0.25-1.

5.

8. The method for preparing a two-component inorganic super-hydrophilic self-cleaning coating according to claim 1, characterized in that: In step (4), the amount of tetraethoxysilane added is 3-5% of the total mass of the modified titanium dioxide sol and the composite alumina sol, and the amount of glutaraldehyde added is 5-10% of the total mass of the modified titanium dioxide sol and the composite alumina sol.

9. A two-component inorganic super hydrophilic self-cleaning coating prepared by the preparation method according to any one of claims 1 to 8.

10. The use of a two-component inorganic super-hydrophilic self-cleaning coating as claimed in claim 9, characterized in that: The self-cleaning coating is used for any one of glass, PET and organic glass, and the coating method of the self-cleaning coating is any one of drip coating, spray coating, brush coating and dipping and pulling.

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