Self-cleaning coating material and method of manufacture, self-cleaning coating, self-cleaning product

Abstract

The present application relates to a kind of self-cleaning coating and preparation method, self-cleaning coating, self-cleaning product, specifically to the modification and application technical field of nanomaterial, the raw material of the self-cleaning coating includes: modifier, sol and polysilane;The mass of the modifier is 0.2-30% of sol mass;The mass ratio of polysilane and sol is (10-30):(70-90).Self-cleaning coating provided by the present application, by utilizing the synergistic effect between modifier, sol and polysilane, active group in coating after spraying is chemically reacted with water vapor and oxygen in air, forms covalent chemical bond, and then reacts with the hydroxyl group on the surface of base material, firmly aims at the surface of base material, forms the all-inorganic system nanometer coating, does not introduce fluorine-containing toxic and harmful elements, and the all-inorganic nanometer coating has excellent base material adhesion, high hardness, weathering resistance and wear resistance.

Description

Technical Field

[0001] This invention relates to the field of nanomaterial modification and application technology, and to a self-cleaning coating and its preparation method, a self-cleaning coating, and a self-cleaning product, particularly to an all-inorganic nano self-cleaning coating and its preparation method, a self-cleaning coating, and self-cleaning glass. Background Technology

[0002] Currently, long-lasting self-cleaning glass can keep the surfaces of architectural glass, automotive glass, and solar panels clean, significantly reducing the adhesion of scale, dust, and dirt, ensuring that the building's appearance remains clean and aesthetically pleasing, greatly enhancing the overall image of the building. It also prevents fogging, improving visibility for vehicles driving in rainy or foggy weather. Furthermore, it improves the photoelectric conversion efficiency of solar panels, saving energy. Therefore, self-cleaning glass can effectively reduce the frequency of manual cleaning and lower maintenance costs.

[0003] For example, CN105198235A discloses a method for preparing hydrophobic and oleophobic self-cleaning glass, the steps of which are as follows: First, silica sol and metal oxide crystal sol are mixed to form a mixed sol, the mixed sol is coated on the glass surface and the glass surface is heat-treated to form a porous structure film; second, fluorosiloxane and siloxane are mixed, hydrolyzed and formed, and the pH of the fluorosiloxane and siloxane solution is adjusted using an inorganic acid to form a fluorosilicone nano-sol; the fluorosilicone nano-sol is coated onto the porous structure film using a coating process, filling and modifying the porous structure film to form a coating layer, and the coating layer is dried and cured to form a hydrophobic and oleophobic composite film. The hydrophobic and oleophobic self-cleaning glass product prepared by this method has good adhesion, high film hardness and abrasion resistance. However, in order to achieve the hydrophobic and self-cleaning effect, this scheme introduces low surface energy organic materials such as fluorosiloxanes. Fluorine-containing substances (such as perfluorinated compounds, PFAS) have extremely high stability and are difficult to degrade. They are highly resistant to ordinary photolysis, hydrolysis and microbial degradation. Once they enter the environment, they are difficult to decompose naturally, which poses a potential risk to the balance of the ecosystem and human safety. Therefore, the restrictions on fluorine-containing substances will become increasingly strict, especially the use of long-chain perfluorinated compounds (such as PFOA and PFOS) will be gradually phased out.

[0004] CN115651534A discloses a superhydrophobic coating, a self-cleaning coating, its preparation method, and its application. It utilizes hydrophobic fumed silica, which has low surface energy and provides the necessary nanostructure for the coating; an epoxy resin with a medium epoxy value, which, after curing, imparts high strength and chemical resistance to the coating; and a colorless, transparent silicone resin, which provides a certain degree of surface roughness and reduces the required curing temperature and time, exhibiting excellent thermal oxidative stability. The resulting coating combines superhydrophobic properties, excellent adhesion, mechanical properties, and high light transmittance. The self-cleaning coating prepared by this material exhibits a static contact angle of up to 171° in pure water, allowing surface impurities such as dust to be easily carried away by the water droplets, demonstrating excellent self-cleaning functionality. However, the hydrophobic fumed silica, silicone resin, and epoxy resin used in this technology are used to construct micro-nano roughness and reduce surface energy using the lotus leaf biomimetic mechanism. When silicone resin and epoxy resin are exposed to sunlight for a long time, they are easily photo-oxidized with oxygen under ultraviolet light, generating free radicals, which leads to the cleavage of the polymer backbone, resulting in discoloration, powdering, and cracking of the coating. Therefore, there are defects in terms of weather resistance.

[0005] The existing technology (Li Jian et al. Preparation of low-adhesion superhydrophobic particle surface by one-step spraying method [J]. Journal of Northwest Normal University: Natural Science Edition, 2014, 50(5):6.) discloses that TiO2 and SiO2 particles are modified to obtain corresponding hydrophobic particles, and then a superhydrophobic particle surface is prepared by spraying. However, due to the weak connection between the silica spheres and the substrate, the hydrophobicity of the surface will decrease after a certain degree of friction.

[0006] In summary, the self-cleaning coatings prepared in the existing technology have defects such as failing to meet environmental protection standards, lacking weather resistance, and insufficient wear resistance. Summary of the Invention

[0007] In view of the problems existing in the prior art, the purpose of the present invention is to provide a self-cleaning coating and its preparation method, a self-cleaning coating, and a self-cleaning product, so as to solve the defects of self-cleaning coatings such as failure to meet environmental protection standards, lack of weather resistance, and lack of wear resistance.

[0008] To achieve this objective, the present invention adopts the following technical solution:

[0009] In a first aspect, the present invention provides a self-cleaning coating, wherein the raw materials of the self-cleaning coating include:

[0010] Modifiers, sols, and polysilanes;

[0011] The modifier accounts for 0.2-30% of the sol mass.

[0012] The mass ratio of the polysilane to the sol is (10-30):(70-90).

[0013] The self-cleaning coating provided by this invention utilizes the synergistic effect between modifiers, sols, and polysilanes. After spraying, the active groups in the coating react chemically with water vapor and oxygen in the air to form covalent chemical bonds, which then react with hydroxyl groups on the substrate surface, firmly anchoring the coating to the substrate surface. The resulting all-inorganic nano-coating system does not introduce any toxic or harmful fluorine-containing elements. The all-inorganic nano-coating exhibits excellent substrate adhesion, high hardness, weather resistance, and wear resistance.

[0014] As a preferred technical solution of the present invention, the functional groups of the modifier include one or a combination of at least two of the following: -CH3, -CH2CH3, -CH2CH2CH3, -Si(OCH3)3, -Si(CH3)2O-, -SO3H, -COOH or -CONH2.

[0015] Preferably, the modifier includes one or a combination of at least two of the following: silane coupling agent, titanate coupling agent, or zirconium coupling agent.

[0016] As a preferred technical solution of the present invention, the sol includes one or a combination of at least two of the following: inorganic nano silica sol, aluminum sol, zirconium sol or titanium sol.

[0017] As a preferred embodiment of the present invention, the polysilane includes: polysiloxane and / or polysilazane.

[0018] In a second aspect, the present invention provides a method for preparing a self-cleaning coating as described in the first aspect, the method comprising:

[0019] Prepare the ingredients according to the recipe;

[0020] A catalyst was added to an alcohol-water solution, followed by a modifier for hydrolysis, to obtain a hydrolysate.

[0021] A sol was added to the hydrolysate to carry out a condensation reaction, resulting in a modified sol.

[0022] Polysilane was added to the modified sol to carry out a hyperbranching reaction, resulting in a self-cleaning coating.

[0023] As a preferred embodiment of the present invention, the alcohol-water solution comprises alcohol and water in a mass ratio of (70-98):(2-30).

[0024] Preferably, the alcohol in the aqueous alcohol solution includes one or a combination of at least two of methanol, ethanol, propanol, ethylene glycol, or isopropanol.

[0025] Preferably, the catalyst comprises one or a combination of at least two of glacial acetic acid, hydrochloric acid, or nitric acid.

[0026] Preferably, the amount of catalyst added is such that the pH value of the alcohol-water solution is controlled to be 3-5.

[0027] Preferably, the mass of the modifier is 2-15% of the mass of the alcohol-water solution.

[0028] Preferably, the hydrolysis includes hydrolysis at 10-40°C for 1-48 hours.

[0029] As a preferred embodiment of the present invention, the temperature of the polycondensation reaction is 60-80℃.

[0030] Preferably, the pH value of the polycondensation reaction is 3-4.

[0031] Preferably, the polycondensation reaction takes 0.5-4 hours.

[0032] As a preferred embodiment of the present invention, the temperature of the hyperbranching reaction is 60-80℃.

[0033] Preferably, the hyperbranching reaction takes 1-48 hours.

[0034] Thirdly, the present invention provides a self-cleaning coating, which is obtained by roller coating, spin coating or spray coating of the self-cleaning coating material as described in the first aspect.

[0035] Fourthly, the present invention provides a self-cleaning product, wherein the surface of the self-cleaning product is provided with the self-cleaning coating described in the third aspect.

[0036] Compared with existing technical solutions, the present invention has the following beneficial effects:

[0037] (1) The self-cleaning coating provided by the present invention achieves surface grafting modification by condensing inorganic sol hydroxyl functional groups and modifier functional groups through a condensation reaction, avoiding the drawbacks of difficult degradation and environmental pollution caused by the introduction of fluorine-containing low surface energy organic reagents; at the same time, a three-dimensional network structure is constructed by hyperbranching reaction of modified polymer and polysilane, which is firmly bonded to the substrate surface through -Si-O-Si- covalent bonds, thereby solving the problem of insufficient adhesion between coating and substrate and easy peeling in traditional technical solutions, and the substrate adhesion can reach level 0.

[0038] (2) After curing, the coating provided by this invention yields an all-inorganic nano-coating system with excellent weather resistance and wear resistance, a service life of several years or more, and a weather resistance of 0.33 Wm. -2 It passes the test at -30~80℃ / 90% humidity for 1000 hours, has abrasion resistance of 500 cycles under a 500g weight, and passes the test after 24 hours of treatment with 0.1mol / LHCl / NaOH.

[0039] The present invention will now be described in further detail. However, the examples described below are merely simplified examples of the present invention and do not represent or limit the scope of protection of the present invention. The scope of protection of the present invention is determined by the claims. Detailed Implementation

[0040] To better illustrate the present invention and facilitate understanding of its technical solutions, typical but non-limiting embodiments of the present invention are as follows:

[0041] Currently, long-lasting self-cleaning glass can keep the surfaces of architectural glass, automotive glass, solar panels, etc., clean, significantly reducing the adhesion of scale, dust, and dirt. In other words, self-cleaning glass can effectively reduce the frequency of manual cleaning and lower maintenance costs. However, existing self-cleaning coatings suffer from shortcomings such as failing to meet environmental standards, poor weather resistance, and insufficient wear resistance. Therefore, this invention optimizes the coating formulation of the self-cleaning coating, utilizing the synergistic effect between modifiers, sols, and polysilanes to achieve a coating with excellent substrate adhesion, high hardness, weather resistance, and wear resistance, as detailed below:

[0042] I. This embodiment provides a self-cleaning coating material, the raw materials of which include:

[0043] Modifiers, sols, and polysilanes.

[0044] The modifier is 0.2-30% of the sol mass, for example, it can be 0.2%, 0.3%, 0.4%, 0.5%, 0.6%, 0.7%, 0.8%, 0.9%, 1%, 2%, 3%, 4%, 5%, 6%, 7%, 8%, 9%, 10%, 12%, 14%, 16%, 18%, 20%, 22%, 24%, 26%, 28%, or 30%, but is not limited to the listed values. Other unlisted values ​​within this range are also acceptable.

[0045] The mass ratio of the polysilane to the sol is (10-30):(70-90), for example, it can be 10:70, 12:72, 14:74, 16:76, 18:78, 20:80, 22:82, 24:84, 26:86, 28:88, 30:90, 10:90 or 30:70, etc., but is not limited to the listed values. Other unlisted values ​​within this range are also acceptable.

[0046] The modified agent comprises one or a combination of at least two of the following groups: -CH3, -CH2CH3, -CH2CH2CH3, -Si(OCH3)3, -Si(CH3)2O-, -SO3H, -COOH or -CONH2.

[0047] The modifier includes one or a combination of at least two of the following: silane coupling agent, titanate coupling agent, or zirconium coupling agent.

[0048] In this invention, the combination of modifiers can be selected as: a combination of silane coupling agent and titanate coupling agent, a combination of titanate coupling agent and zirconium coupling agent, a combination of silane coupling agent and zirconium coupling agent, etc.

[0049] In this invention, the silane coupling agent may be selected as one or a combination of at least two of the following: silane coupling agent KH550, silane coupling agent KH560, and silane coupling agent KH570.

[0050] In this invention, the titanate coupling agent may be selected from one or a combination of at least two of HY75 (di(acetylacetonyl)titanate), HY201 (isopropyltris(dioctylpyrophosphate)titanate), and TCA-TE (bis(triethanolamine)diisopropoxytitanate).

[0051] In this invention, the zirconium coupling agent may be selected from one or a combination of at least two of Nano Zr-MA, Zr-EP sol, Cavedon AZ series, aluminum-zirconate coupling agent, tetra-n-propylzirconate (TPOZ), and tetrabutylzirconate.

[0052] In this invention, different functional groups are introduced by adjusting the type of modifier, resulting in different water contact angles. A water contact angle higher than 90° indicates hydrophobic self-cleaning, while a water contact angle lower than 20° indicates hydrophilic self-cleaning. For example, functional groups such as amino, sulfonic acid, hydroxyl, and carboxyl groups in the modifier have hydrophilic properties and can be used to prepare hydrophilic nanocoatings by grafting modified functional groups; functional groups such as methyl, ethyl, propyl, aliphatic, and silyl groups in the modifier have hydrophobic properties and can be used to prepare hydrophobic nanocoatings by grafting modified functional groups.

[0053] The sol includes one or a combination of at least two of the following: inorganic nano-silica sol, aluminum sol, zirconium sol, or titanium sol.

[0054] In this invention, the particle size of the particles in the sol is 5-50 nm, for example, it can be 5 nm, 9.5 nm, 14 nm, 18.5 nm, 23 nm, 27.5 nm, 32 nm, 36.5 nm, 41 nm, 45.5 nm or 50 nm, but is not limited to the listed values. Other unlisted values ​​within this range are also acceptable.

[0055] In this invention, the mass percentage of particles in the sol is 10-30%, for example, it can be 10%, 12%, 14%, 16%, 18%, 20%, 22%, 24%, 26%, 28% or 30%, etc., but is not limited to the listed values. Other unlisted values ​​within this range are also acceptable.

[0056] In this invention, the sol can be obtained by purchasing commercially available products according to certain requirements, or by preparing it according to existing technology.

[0057] The polysilanes include: polysiloxanes and / or polysilazanes.

[0058] In this invention, the polysiloxane can be selected from linear polysiloxane, polydimethylsiloxane, cyclic siloxane, branched / crosslinked siloxane, etc., and can be selected from commercially available products or prepared according to existing technology.

[0059] In this invention, the polysilazane can be selected from perhydropolysilazane PHPS, methyl-modified PSZ, vinyl-modified PSZ, epoxy / amino functional PSZ, etc., and can be selected from commercially available products or prepared according to existing technology.

[0060] II. This embodiment provides a method for preparing a self-cleaning coating, the method comprising:

[0061] Prepare the ingredients according to the recipe;

[0062] A catalyst was added to an alcohol-water solution, followed by a modifier for hydrolysis, to obtain a hydrolysate.

[0063] A sol was added to the hydrolysate to carry out a condensation reaction, resulting in a modified sol.

[0064] Polysilane was added to the modified sol to carry out a hyperbranching reaction, resulting in a self-cleaning coating.

[0065] The alcohol-water solution comprises alcohol and water in a mass ratio of (70-98):(2-30), such as 70:2, 72.8:4.8, 75.6:7.6, 78.4:10.4, 81.2:13.2, 84:16, 86.8:18.8, 89.6:21.6, 92.4:24.4, 95.2:27.2, 98:30, 98:2, or 70:30, but is not limited to the listed values. Other unlisted values ​​within this range are also acceptable.

[0066] The alcohol in the aqueous solution includes one or a combination of at least two of methanol, ethanol, propanol, ethylene glycol, or isopropanol.

[0067] In this invention, the combination of alcohols can be selected as: a combination of methanol and ethanol, a combination of ethanol and propanol, a combination of propanol and ethylene glycol, a combination of ethylene glycol and isopropanol, a combination of ethanol and isopropanol, etc.

[0068] The catalyst includes one or a combination of at least two of glacial acetic acid, hydrochloric acid, or nitric acid.

[0069] In this invention, the combination of catalysts can be selected as a combination of glacial acetic acid and hydrochloric acid, a combination of hydrochloric acid and nitric acid, or a combination of nitric acid and glacial acetic acid.

[0070] In this invention, the concentration of glacial acetic acid is 0.4-0.6 mol / L, for example, it can be 0.4 mol / L, 0.42 mol / L, 0.44 mol / L, 0.46 mol / L, 0.48 mol / L, 0.5 mol / L, 0.52 mol / L, 0.54 mol / L, 0.56 mol / L, 0.58 mol / L or 0.6 mol / L, etc., but is not limited to the listed values. Other unlisted values ​​within this range are also acceptable.

[0071] In this invention, the mass concentration of hydrochloric acid is 0.1-0.2 mol / L, for example, it can be 0.1 mol / L, 0.11 mol / L, 0.12 mol / L, 0.13 mol / L, 0.14 mol / L, 0.15 mol / L, 0.16 mol / L, 0.17 mol / L, 0.18 mol / L, 0.19 mol / L or 0.2 mol / L, etc., but is not limited to the listed values. Other unlisted values ​​within this range are also acceptable.

[0072] In this invention, the mass concentration of nitric acid is 0.1-0.2 mol / L, for example, it can be 0.1 mol / L, 0.11 mol / L, 0.12 mol / L, 0.13 mol / L, 0.14 mol / L, 0.15 mol / L, 0.16 mol / L, 0.17 mol / L, 0.18 mol / L, 0.19 mol / L or 0.2 mol / L, etc., but is not limited to the listed values. Other unlisted values ​​within this range are also acceptable.

[0073] The amount of catalyst added is such that the pH value of the alcohol-water solution is controlled to be 3-5, for example, it can be 3, 3.2, 3.4, 3.6, 3.8, 4, 4.2, 4.4, 4.6, 4.8 or 5, but is not limited to the listed values. Other unlisted values ​​within this range are also acceptable.

[0074] The modifier is 2-15% of the mass of the alcohol-water solution, for example, it can be 2%, 3.3%, 4.6%, 5.9%, 7.2%, 8.5%, 9.8%, 11.1%, 12.4%, 13.7% or 15%, etc., but is not limited to the listed values. Other unlisted values ​​within this range are also acceptable.

[0075] The hydrolysis includes hydrolysis at 10-40℃ for 1-48 hours, for example, 1 hour, 2 hours, 4 hours, 6 hours, 8 hours, 10 hours, 12 hours, 14 hours, 16 hours, 18 hours, 20 hours, 22 hours, 24 hours, 26 hours, 28 hours, 30 hours, 32 hours, 34 hours, 36 hours, 38 hours, 40 hours, 42 hours, 44 hours, 46 hours, or 48 hours, but is not limited to the listed values. Other unlisted values ​​within this range are also acceptable.

[0076] The temperature of the polycondensation reaction is 60-80℃, for example, it can be 60℃, 62℃, 64℃, 66℃, 68℃, 70℃, 72℃, 74℃, 76℃, 78℃ or 80℃, but is not limited to the listed values. Other unlisted values ​​within this range are also acceptable.

[0077] The polycondensation reaction time is 0.5-4h, for example, it can be 0.5h, 0.85h, 1.2h, 1.55h, 1.9h, 2.25h, 2.6h, 2.95h, 3.3h, 3.65h or 4h, but is not limited to the listed values. Other unlisted values ​​within this range are also acceptable.

[0078] The temperature of the hyperbranching reaction is 60-80℃, for example, it can be 60℃, 62℃, 64℃, 66℃, 68℃, 70℃, 72℃, 74℃, 76℃, 78℃ or 80℃, but is not limited to the listed values. Other unlisted values ​​within this range are also acceptable.

[0079] The hyperbranching reaction time is 1-48h, for example, it can be 1h, 2h, 4h, 6h, 8h, 10h, 12h, 14h, 16h, 18h, 20h, 22h, 24h, 26h, 28h, 30h, 32h, 34h, 36h, 38h, 40h, 42h, 44h, 46h, or 48h, but is not limited to the listed values. Other unlisted values ​​within this range are also acceptable.

[0080] In this invention, the coating is cured at room temperature or at a certain temperature after being applied to obtain an inorganic nano-coating with a nanoscale thickness. For example, the room temperature (10-40℃) curing time is 5 min to 24 h, the heating curing conditions are 80-150℃ for 10-30 min, and the more preferred heating curing conditions are 100-150℃ for 10-15 min.

[0081] In this invention, the surface of the substrate can be cleaned and activated before the coating is applied. For example, plasma irradiation can be used to remove oil stains from the surface of glass, ceramics, metals, etc., which can enhance the interfacial adhesion to a certain extent. Furthermore, the surface of the substrate can be hydroxylated to improve the bonding effect between the coating and the substrate.

[0082] In this invention, the substrate can be selected from glass, ceramic, metal, or leather, but is preferably glass.

[0083] III. This embodiment provides a self-cleaning coating, which is obtained by roller coating, spin coating or spray coating of self-cleaning coating paint.

[0084] IV. This embodiment provides a self-cleaning product, wherein the surface of the self-cleaning product is provided with a self-cleaning coating.

[0085] V. To illustrate the excellent performance of the self-cleaning coating obtained by curing the coating provided by this invention, the following example is used for explanation:

[0086] Example 1

[0087] This embodiment provides a self-cleaning coating material, the preparation process of which is as follows:

[0088] 1. Prepare 100 mL of 95% ethanol aqueous solution, add a small amount of glacial acetic acid (concentration of 0.5 mol / L), control the pH value of the system at 3, slowly add 5 g of silane coupling agent KH570, and hydrolyze at room temperature (25℃) for 24 h to obtain a pre-hydrolyzed solution A with hydrophobic groups;

[0089] 2. In the above solution A, 45g of acidic silica sol with a solid content of 30% (pH value of 4) was added dropwise. The temperature of the system was adjusted to 60℃ and the pH value was adjusted to 3. The pre-hydrolyzed coupling agent surface groups and the active hydroxyl groups (-OH) on the sol surface underwent a condensation reaction for 2h, and the groups were then grafted onto the surface of the sol particles to obtain modified silica sol system B with hydrophobic function.

[0090] 3. Add the above modified silica sol system B to 9g of methyl modified PSZ, raise the reaction temperature of the system to 70℃, and obtain a hyperbranched macromolecular structure coating with a three-dimensional network structure through functional group polymerization and hyperbranching reaction for 48h.

[0091] 4. Apply the above coating evenly to the surface of the glass substrate using a spin coating process, and cure at room temperature (25°C) for 1 hour to obtain an inorganic nano-coating with hydrophobic function and hydrophobic glass.

[0092] Example 2

[0093] This embodiment provides a self-cleaning coating material, the preparation process of which is as follows:

[0094] 1. Prepare 100 mL of ethylene glycol aqueous solution with a mass dispersion of 90%, add a small amount of hydrochloric acid (0.1 mol / L), control the pH value of the system at 5, slowly add 10 g of silane coupling agent KH550, and hydrolyze at room temperature (25℃) for 12 h to obtain a pre-hydrolyzed solution A with hydrophilic groups;

[0095] 2. In the above solution A, 76g of acidic titanium sol with a solid content of 30% (pH value of 4) was added dropwise. The temperature of the system was adjusted to 60℃ and the pH value was adjusted to 4. The pre-hydrolyzed coupling agent surface groups and the active hydroxyl groups (-OH) on the surface of the titanium sol underwent a condensation reaction for 1 hour, thereby grafting the groups onto the surface of the titanium sol particles to obtain modified titanium sol system B with hydrophilic function.

[0096] 3. Add the above modified titanium sol system B to 24g of amino-functionalized PSZ, maintain the reaction temperature of the system at 60℃, and obtain a hyperbranched macromolecular structure coating with a three-dimensional network structure through functional group polymerization and hyperbranching reaction for 12h.

[0097] 4. Apply the above coating evenly to the surface of the glass substrate using a spin coating process, and cure at 150°C for 10 minutes to obtain an inorganic nano-coating with hydrophilic function and self-cleaning glass.

[0098] Example 3

[0099] This embodiment provides a self-cleaning coating material, the preparation process of which is as follows:

[0100] 1. Prepare 100 mL of isopropanol aqueous solution with a mass dispersion of 85%, add a small amount of dilute nitric acid (0.1 mol / L), control the pH value of the system at 4, slowly add 5 g of titanate coupling agent HY201, and hydrolyze at room temperature (25℃) for 2 h to obtain a pre-hydrolyzed solution A with hydrophobic groups;

[0101] 2. In the above solution A, 85g of zirconium sol with a solid content of 30% was added dropwise. The temperature of the system was adjusted to 60℃ and the pH value was 3. The pre-hydrolyzed coupling agent surface groups and the active hydroxyl groups (-OH) on the zirconium sol surface underwent a condensation reaction for 2h, and then the groups were grafted onto the surface of the sol particles to obtain modified zirconium sol system B with hydrophobic function.

[0102] 3. Add the above modified zirconium sol system B to 22g of methyl modified PSZ, raise the reaction temperature of the system to 65℃, and obtain a hyperbranched macromolecular structure coating with a three-dimensional network structure through functional group polymerization and hyperbranching reaction for 36h.

[0103] 4. Apply the above coating evenly to the surface of the glass substrate by spraying, and cure at room temperature (25℃) for 10 hours to obtain an inorganic nano-coating with hydrophobic function and hydrophobic glass.

[0104] Example 4

[0105] This embodiment provides a self-cleaning coating material, the preparation process of which is as follows:

[0106] 1. Prepare 100 mL of ethanol aqueous solution with a mass dispersion of 90%, add a small amount of glacial acetic acid (0.5 mol / L), control the pH value of the system at 5, slowly add 5 g of silane coupling agent KH570, and hydrolyze at room temperature (25℃) for 18 h to obtain a pre-hydrolyzed solution A with hydrophobic groups;

[0107] 2. In the above solution A, 50g of silica sol, 15g of titanium sol, and 15g of aluminum sol with a total solid content of 30% were added dropwise. The temperature of the system was adjusted to 60℃ and the pH value was 3. The pre-hydrolyzed coupling agent surface groups reacted with the active hydroxyl groups (-OH) on the silica sol, titanium sol, and aluminum sol surface through a condensation reaction for 4 hours, thereby grafting the groups onto the surface of the composite sol particles to obtain a modified composite sol system B with hydrophobic function.

[0108] 3. Add the above modified composite sol system B to 20g of methyl modified PSZ, raise the reaction temperature of the system to 70℃, and obtain a hyperbranched macromolecular structure coating with a three-dimensional network structure through functional group polymerization and hyperbranching reaction for 48h.

[0109] 4. Apply the above coating evenly to the surface of the glass substrate using a roller coating process, and cure at 80°C for 0.5 hours to obtain an inorganic nano-coating with hydrophobic function and hydrophobic glass.

[0110] Comparative Example 1

[0111] The only difference from Example 1 is that the methyl-modified PSZ is replaced with an equal amount of methylchlorosilane.

[0112] Comparative Example 2

[0113] The only difference from Example 1 is that the methyl-modified PSZ is replaced with an equal amount of phenylchlorosilane.

[0114] Comparative Example 3

[0115] The only difference from Example 1 is that the modifier is replaced with an equal amount of methylchlorosilane.

[0116] Comparative Example 4

[0117] The only difference from Example 1 is that the modifier is replaced with an equal amount of phenylchlorosilane.

[0118] Comparative Example 5

[0119] The only difference from Example 1 is that the methyl-modified PSZ is replaced with an equal amount of hexamethyldisilazane.

[0120] Comparative Example 6

[0121] The only difference from Example 1 is that methyl-modified PSZ is not added during the preparation process.

[0122] Comparative Example 7

[0123] The only difference from Example 1 is that the mass of the silane coupling agent is 16g, and the mass of the modifier is 35.6% of the sol mass.

[0124] Comparative Example 8

[0125] The only difference from Example 1 is that the mass of methyl-modified PSZ is 3g, and the mass ratio of polysilane to sol is 6:90.

[0126] Comparative Example 9

[0127] The only difference from Example 1 is that the mass of methyl-modified PSZ is 20g, and the mass ratio of polysilane to sol is 40:90.

[0128] The inorganic nano-coatings and hydrophobic glasses obtained in the above embodiments and comparative examples were subjected to physicochemical property tests and characterization, as detailed below:

[0129] The adhesion was tested according to the cross-cut test of GB / T 9286-2021, with a cross-cut tool, a cross-cut of 1 mm, a spacing of 6×6 grid, and 3M 600 tape applied and quickly peeled off, with a rating of 0-5.

[0130] Hardness was tested according to GB / T 6739-2006 Pencil Hardness Tester (500g load); Pencil: Scratching in sequence from 9H to 9B, a passing grade is one where a 5mm scratch is continuously formed;

[0131] Weather resistance was tested according to GB / T 14522-2008, with the UV weathering test chamber parameters set to 0.33 Wm. -2 Cycled for 1000 hours at -30°C to 80°C and 90% humidity, the standard is: contact angle change Δθ < 5°;

[0132] Wear resistance was tested according to GB / T 23988-2009 reciprocating grinding. After 500 reciprocating cycles under a 500g load, the weight loss and contact angle were measured using a reciprocating grinding wear tester (JM-V). The passing standard was: contact angle change Δθ < 5°.

[0133] Acid and alkali resistance was tested according to the drop method of GB / T 9274-1988. In a constant temperature and humidity chamber, 0.1 mol / L HCl and 0.1 mol / L NaOH were immersed for 24 hours at room temperature of 25°C and humidity of 50%, respectively. After rinsing, the coating was checked for discoloration, blistering, peeling and failure of coating function. The passing standard was: contact angle change Δθ < 5°.

[0134] Hydrophobic and hydrophilic angles were measured according to GB / T 30693-2014; contact angle meter (VCAOptima), 2μL deionized water, static drip method, room temperature 23℃, RH 50%, averaged at 5 points per piece;

[0135] The results are shown in Table 1 below.

[0136] Table 1

[0137]

[0138] As shown in Table 1:

[0139] In Comparative Example 3, the hydrolysis of methyltrichlorosilane also yielded a low surface energy polysiloxane network containing -CH3, which has good hydrophobic properties. However, the hydrolysis rate of methyltrichlorosilane is very fast, the exothermic reaction is intense, the process is difficult to control, the film quality is poor, and the hydrolysis products contain HCl, which has a certain degree of corrosivity.

[0140] Comparative Example 4 used phenyltrichlorosilane, which, compared with methyltrichlorosilane, formed a phenyl-containing polysiloxane network after hydrolysis and condensation, resulting in a lower surface energy (≈22 mNm). -1 The rigidity of the benzene rings significantly improves the coating's hardness, heat resistance (>400℃), and wear resistance; the π-π stacking of benzene rings can generate additional roughness at the nanoscale, making it easier to obtain a high contact angle. However, it also suffers from drawbacks such as a very fast hydrolysis rate, intense exothermic reaction, difficulty in process control, poor film quality, and the presence of HCl in the hydrolysis products.

[0141] Comparative Example 5: Hexamethyldisilazane is a small molecule dimer with no film-forming properties, while methyl-modified PSZ is a high molecular polymer with film-forming properties and bonds to the glass substrate through chemical bonding.

[0142] Comparative Examples 1 and 2 follow the same mechanism, but methylchlorosilane and phenylchlorosilane do not have film-forming properties in the formulations of this invention.

[0143] Comparative Example 6, without the addition of polysilane polymer, cannot hybridize to form hyperbranched polymers, affecting film-forming properties and adhesion to the substrate.

[0144] In Comparative Example 7, an excess of silane coupling agent was introduced. After hydrolysis, an excess of -OH chemical bonds were formed. These bonds reacted with the -OH on the surface of the modified silica gel, reducing the -OH content on the silica gel surface and thus decreasing its activity, which was not conducive to the subsequent hybridization reaction.

[0145] The comparative example showed that the content of methyl-modified PSZ was too low, which prevented the formation of a continuous phase, resulting in insufficient film thickness. After curing, the film was loose and porous, and its mechanical strength and barrier properties decreased significantly.

[0146] Comparative Example 9: The methyl-modified PSZ content was too high, resulting in a sharp increase in viscosity, making coating difficult, easily leaving scratches, and causing volume shrinkage of more than 50% during curing. The shrinkage stress concentration caused microcracks / crazing, which affected the film quality.

[0147] The preferred embodiments of the present invention have been described in detail above. However, the present invention is not limited to the specific details in the above embodiments. Within the scope of the technical concept of the present invention, various simple modifications can be made to the technical solution of the present invention, and these simple modifications all fall within the protection scope of the present invention.

[0148] It should also be noted that the various specific technical features described in the above specific embodiments can be combined in any suitable manner without contradiction. In order to avoid unnecessary repetition, the present invention will not describe the various possible combinations separately.

[0149] Furthermore, various different embodiments of the present invention can be combined in any way, as long as they do not violate the spirit of the present invention, they should also be regarded as the content disclosed by the present invention.

Claims

1. A self-cleaning coating, characterized in that, The raw materials for the self-cleaning coating include: Modifiers, sols, and polysilanes; The modifier accounts for 0.2-30% of the sol mass. The mass ratio of the polysilane to the sol is (10-30):(70-90).

2. The self-cleaning coating as described in claim 1, characterized in that, The groups of the modifier include one or a combination of at least two of the following: -CH3, -CH2CH3, -CH2CH2CH3, -Si(OCH3)3, -Si(CH3)2O-, -SO3H, -COOH or -CONH2; Preferably, the modifier includes one or a combination of at least two of the following: silane coupling agent, titanate coupling agent, or zirconium coupling agent.

3. The self-cleaning coating as described in claim 1, characterized in that, The sol includes one or a combination of at least two of the following: inorganic nano silica sol, aluminum sol, zirconium sol, or titanium sol.

4. The self-cleaning coating as described in claim 1, characterized in that, The polysilanes include: polysiloxanes and / or polysilazanes.

5. A method for preparing a self-cleaning coating as described in any one of claims 1-4, characterized in that, The preparation method includes: Prepare the ingredients according to the recipe; A catalyst was added to an alcohol-water solution, followed by a modifier for hydrolysis, to obtain a hydrolysate. A sol was added to the hydrolysate to carry out a condensation reaction, resulting in a modified sol. Polysilane was added to the modified sol to carry out a hyperbranching reaction, resulting in a self-cleaning coating.

6. The preparation method according to claim 5, characterized in that, The alcohol-water solution comprises alcohol and water in a mass ratio of (70-98):(2-30); Preferably, the alcohol in the aqueous alcohol solution includes one or a combination of at least two of methanol, ethanol, propanol, ethylene glycol, or isopropanol; Preferably, the catalyst comprises one or a combination of at least two of glacial acetic acid, hydrochloric acid, or nitric acid; Preferably, the amount of catalyst added is such that the pH value of the alcohol-water solution is controlled to be 3-5; Preferably, the mass of the modifier is 2-15% of the mass of the alcohol-water solution; Preferably, the hydrolysis includes hydrolysis at 10-40°C for 1-48 hours.

7. The preparation method according to claim 5, characterized in that, The temperature of the polycondensation reaction is 60-80℃; Preferably, the pH value of the polycondensation reaction is 3-4; Preferably, the polycondensation reaction takes 0.5-4 hours.

8. The preparation method according to claim 5, characterized in that, The temperature of the hyperbranching reaction is 60-80℃; Preferably, the hyperbranching reaction takes 1-48 hours.

9. A self-cleaning coating, characterized in that, The self-cleaning coating is obtained by roller coating, spin coating or spraying of the self-cleaning coating material as described in any one of claims 1-4.

10. A self-cleaning product, characterized in that, The surface of the self-cleaning product is provided with the self-cleaning coating as described in claim 9.

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