Nano protective coating based on water-based paint and production process thereof

Abstract

The invention relates to the technical field of preparation of protective coatings, in particular to a nano protective coating based on water-based paint and a production process of the nano protective coating. The coating is prepared from the following components in parts by mass: 50 to 60 parts of waterborne polyurethane resin, 10 to 20 parts of fluorocarbon modified polysiloxane, 14 to 23 parts of modified nano filler composition, 3 to 5 parts of ammonium polyphosphate, 10 to 12 parts of waterborne fluorocarbon emulsion, 1 to 3 parts of silane coupling agent, 1 to 2 parts of dispersing agent, 2 to 4 parts of coalescing agent, 1 to 2 parts of thickening agent, 0.5 to 1 part of defoaming agent, 10 to 15 parts of cosolvent and 20 to 40 parts of deionized water. According to the invention, by selecting the raw materials of specific types and dosages, the prepared nano protective coating has excellent waterproof and fireproof performance, also has the advantages of strong adhesive force, environmental protection and high hardness, can be suitable for most coating application scenes, and has significant economic prospects.

Description

Technical Field

[0001] The present invention relates to the technical field of protective coating preparation, and particularly relates to a nano protective coating based on waterborne paint and its production process. Background Art

[0002] With the improvement of infrastructure, the booming development of fields such as the construction industry, and the rapid growth of industrial production, the use of coatings shows a significant upward trend. Traditional coatings mainly use organic substances as the dispersion medium, and the organic volatile compounds (VOCs) released by them, especially formaldehyde and aromatic hydrocarbons, have a serious impact on human health. In recent years, with the gradual enhancement of people's environmental protection awareness and the increasingly strict relevant laws and regulations on the production and use of chemical products, waterborne coatings have been favored by consumers due to their green, environmental protection, and low-carbon advantages, and are gradually replacing the dominant position of traditional coatings, which is an important direction for the development of coatings today. Waterborne coatings refer to coatings that use water as a solvent or dispersion medium. Compared with traditional organic solvent-based coatings, waterborne coatings can not only reduce the emission of organic volatile compounds, but also save resources and energy, and are also convenient for storage and transportation. Although waterborne coatings have environmental protection advantages, their technical limitations are still significant. First, the hydrophilic characteristics of the film-forming substances in the basic formula lead to insufficient water resistance of the coating, and it is prone to osmotic peeling or bubbling in a long-term humid environment, and the waterproof performance is significantly lower than that of traditional solvent-based coatings. Second, there is a lack of efficient fire protection system design, and the fire resistance limit and smoke suppression performance of existing waterborne coatings are difficult to meet the requirements of building fire protection codes, and the problem of poor compatibility between fire protection additives and waterborne systems further exacerbates the fire protection performance defects. In addition, traditional defects such as slow drying rate (about 30% longer than solvent-based coatings) and low mechanical strength have not been completely overcome, which directly affects the construction efficiency and coating durability.

[0003] Therefore, developing a nano protective coating that can solve the above-mentioned disadvantages of waterborne coatings not only has great environmental protection significance but also has high economic value.

[0004] In order to overcome the deficiencies in the prior art, the purpose of the present invention is to provide a nano protective coating based on waterborne paint and its production process, which includes the following components by mass: 50 - 60 parts of waterborne polyurethane resin, 10 - 20 parts of fluorocarbon-modified polysiloxane, 14 - 23 parts of modified nano filler composition, 3 - 5 parts of ammonium polyphosphate, 10 - 12 parts of waterborne fluorocarbon emulsion, 1 - 3 parts of silane coupling agent, 1 - 2 parts of dispersant, 2 - 4 parts of film-forming aid, 1 - 2 parts of thickener, 0.5 - 1 part of defoamer, 10 - 15 parts of cosolvent, and 20 - 40 parts of deionized water. By selecting specific types and dosages of each raw material, the nano protective coating prepared by the present invention has excellent waterproof and fireproof properties, and at the same time has the advantages of strong adhesion, environmental protection, and high hardness, and can be applied to most coating application scenarios, having significant economic prospects.

[0005] To achieve the above object, the present invention provides the following technical solutions: A nano protective coating based on waterborne paint, comprising the following components by mass: 50 - 60 parts of waterborne polyurethane resin, 10 - 20 parts of fluorocarbon modified polysiloxane, 14 - 23 parts of modified nano filler composition, 3 - 5 parts of ammonium polyphosphate, 10 - 12 parts of waterborne fluorocarbon emulsion, 1 - 3 parts of silane coupling agent, 1 - 2 parts of dispersant, 2 - 4 parts of film forming auxiliary, 1 - 2 parts of thickener, 0.5 - 1 part of defoaming agent, 10 - 15 parts of cosolvent, 20 - 40 parts of deionized water.

[0006] Preferably, the modified nano filler composition is a mixture of nano silica, nano alumina, and nano aluminum hydroxide in a mass ratio of 5:3:2.

[0007] Preferably, the modified nano filler composition is prepared by the following steps: S11. Weigh the corresponding masses of nano silica, nano alumina, and nano aluminum hydroxide respectively according to the ratio, and perform activation treatment at 180 - 200 °C for 2 - 3 h. S12. Mix the silane coupling agent with an ethanol aqueous solution with a concentration of 30 - 40% according to the ratio to prepare a grafting treatment solution. S13. Immerse the activated nano silica, nano alumina, and nano aluminum hydroxide into the grafting treatment solution in sequence, stir and react at 80 - 90 °C for 3 - 4 h, centrifuge, wash, and dry to obtain a pre - modified nano filler composition. S14. Mix the pre - modified nano filler composition with 1 - 2% of triethyl phosphate by addition amount, and stir and react at 60 - 70 °C for 1 - 2 h to obtain the modified nano filler composition.

[0008] Preferably, in step S12, the ratio of the silane coupling agent to the ethanol aqueous solution is 2 - 3:90 - 100; the pH of the grafting treatment solution is controlled at 4 - 5.

[0009] Preferably, in step S12, the silane coupling agent is selected from one or more of γ - aminopropyltriethoxysilane and γ - methacryloxypropyltrimethoxysilane.

[0010] Preferably, the fluorocarbon modified polysiloxane is prepared by the following steps: S21. Dissolve 10 - 15 parts of (3,3,3 - trifluoropropyl)methyldichlorosilane in 50 - 60 parts of toluene by mass, hydrolyze at 40 - 100 °C for 2 - 4 h to generate a fluorinated hydrolyzed homopolymer. S22. Add 8 - 9 parts of octamethylcyclotetrasiloxane, 1 - 2 parts of methyltrifluoropropylcyclotrisiloxane, 0.3 - 0.5 parts of hexamethyldisiloxane and 0.01 - 0.1 parts of p - toluenesulfonic acid to the fluorine - containing hydrolyzed homopolymer in sequence, and polymerize at 60 - 120 °C for 6 - 12 h to finally obtain fluorocarbon - modified polysiloxane.

[0011] Preferably, the dispersant is a polyacrylate - type dispersant; the thickener is a polyurethane - associative thickener; the defoamer is a silicone - type defoamer.

[0012] Preferably, the cosolvent is selected from one or more of propylene glycol, ethylene glycol butyl ether, and dipropylene glycol methyl ether; the film - forming aid is selected from one or more of propylene glycol phenyl ether and dodecyl alcohol ester.

[0013] A production process of a nano - protective coating based on water - borne paint for producing the nano - protective coating, comprising the following steps: S1. Mix water - borne polyurethane resin, fluorocarbon - modified polysiloxane, modified nano - filler composition, ammonium polyphosphate, and silane coupling agent in proportion, heat up to 60 - 80 °C and stir for 2 - 3 h, and obtain a primary coating after cooling to room temperature. S2. Add water - borne fluorocarbon emulsion, dispersant, film - forming aid, thickener, defoamer, cosolvent, and deionized water to the primary coating in proportion in sequence, heat up to 80 - 100 °C and stir for 1 - 2 h, and obtain the nano - protective coating based on water - borne paint after cooling to room temperature.

[0014] Preferably, the silane coupling agent is selected from one or more of γ - aminopropyltriethoxysilane and γ - methacryloxypropyltrimethoxysilane.

[0015] Compared with the prior art, the beneficial effects of the present invention are as follows: 1. The present invention constructs a functional composite water - borne coating system through multi - component synergy. With the organic - inorganic hybridization technology as the core, it systematically solves the balance problem between mechanical properties and functionality. The film - forming system uses water - borne polyurethane resin and fluorocarbon - modified polysiloxane to form a dynamic cross - linked network through the bonding of urethane groups and siloxane segments, and with the gradient dual - fluorine modification design, it synchronously improves the mechanical strength and hydrophobic and anti - corrosion properties. 2. The modified nano - filler composition can achieve nano - level dispersion strengthening through the surface grafting technology of triethyl phosphate and form a dense composite three - dimensional framework structure in the resin matrix through directional cross - linking with silane coupling agent, thereby greatly reducing the wear rate and significantly improving the adhesion of the coating; in a fire field environment, ammonium polyphosphate and nano - Al(OH)3 in the modified nano - filler composition can jointly catalyze the cracking of fluorocarbon - modified polysiloxane to generate a Si - F / P - O - F flame - retardant network. 3. The C-F short chains of the aqueous fluorocarbon emulsion can spontaneously migrate to the coating surface layer driven by entropy, form a dense hydrophobic layer with the long fluoroalkyl side chains of the fluorocarbon-modified polysiloxane, reduce the surface energy of the coating, and thus achieve the self-cleaning function through the lotus effect. Description of the Drawings

[0016] Figure 1 It is the process flow chart of the preparation of the nano-protective coating based on aqueous paint according to the present invention; Figure 2 It is the process flow chart of the preparation of the modified nano-filler composition according to the present invention; Figure 3 It is the process flow chart of the preparation of the fluorocarbon-modified polysiloxane according to the present invention; Figure 4 It is the effect diagram of the adhesion test of Example 1, Example 2 and Comparative Example 3 of the present invention, wherein, (a) is Example 1, (b) is Example 2, and (c) is Comparative Example 3. Detailed Embodiments

[0017] Next, the present invention will be clearly and completely described in conjunction with the embodiments of the present invention. Obviously, the described embodiments are only a part of the embodiments of the present invention, rather than all the embodiments. All other embodiments obtained by those of ordinary skill in the art based on the embodiments of the present invention without creative efforts shall fall within the protection scope of the present invention.

[0018] Please refer to Figures 1-4 , the present invention provides a technical solution: Example 1, a production process of a nano-protective coating based on aqueous paint: S1. Mix the aqueous polyurethane resin, fluorocarbon-modified polysiloxane, modified nano-filler composition, ammonium polyphosphate, and silane coupling agent in proportion, heat up to 75 °C and stir for 2.5 h, and obtain the primary coating after cooling to room temperature; S2. Add the aqueous fluorocarbon emulsion, dispersant, film-forming aid, thickener, defoamer, co-solvent, and deionized water to the primary coating in proportion, heat up to 100 °C and stir for 1 h, and obtain the nano-protective coating based on aqueous paint after cooling to room temperature.

[0019] In the above process, each component is in parts by mass, and the dosage is as follows (it is stipulated that one unit part by mass is 50 g):

[0020] The brand of the aqueous polyurethane resin is HYDRAN AP-30F; The model of the aqueous fluorocarbon emulsion is FX-970; The silane coupling agent is γ-aminopropyltriethoxysilane; The dispersant is a polyacrylate dispersant, specifically lithium polyacrylate; The film-forming auxiliary is propylene glycol phenyl ether; The thickener is a polyurethane associative thickener, specifically RM-2020; The defoamer is a silicone defoamer, specifically DC-200; The co-solvent is propylene glycol; In the above process, the modified nano-filler composition is a mixture of nano-silica, nano-alumina, and nano-aluminum hydroxide with a mass ratio of 5:3:2; The modified nano-filler composition is prepared by the following steps: S11. Weigh 5 parts of nano-silica, 3 parts of nano-alumina, and 2 parts of nano-aluminum hydroxide by mass, and perform activation treatment at 180 °C for 2 h; S12. Mix 2 parts of γ-aminopropyltriethoxysilane with 90 parts of an ethanol aqueous solution with a concentration of 30% to prepare a grafting treatment solution, and control the pH of the grafting treatment solution to 4; S13. Immerse the activated nano-silica, nano-alumina, and nano-aluminum hydroxide into the grafting treatment solution in sequence, stir and react at 80 °C for 3 h, centrifuge, wash, and dry to obtain a pre-modified nano-filler composition; S14. Mix the pre-modified nano-filler composition with 1% of triethyl phosphate by addition amount, stir and react at 60 °C for 1 h to obtain the modified nano-filler composition. Repeat the above steps cyclically to prepare a large amount of the modified nano-filler composition, and take 21 parts for the preparation of the nano-protective coating.

[0021] In the above process, the fluorocarbon-modified polysiloxane is prepared by the following steps: S21. Dissolve 13 parts of (3,3,3-trifluoropropyl)methyldichlorosilane in 55 parts of toluene, and hydrolyze at 60 °C for 2 h to generate a fluorinated hydrolyzed homopolymer; S22. Add 8 parts of octamethylcyclotetrasiloxane, 1 part of methyltrifluoropropylcyclotrisiloxane, 0.5 part of hexamethyldisiloxane, and 0.07 part of p-toluenesulfonic acid to the fluorinated hydrolyzed homopolymer in sequence, and polymerize at 80 °C for 10 h to finally obtain the fluorocarbon-modified polysiloxane.

[0022] Example 2, a production process of a nano-protective coating based on waterborne paint: S1. Mix the waterborne polyurethane resin, fluorocarbon-modified polysiloxane, modified nano-filler composition, ammonium polyphosphate, and silane coupling agent in proportion, heat up to 65 °C and stir for 2 h, and cool to room temperature to obtain a primary coating; S2. Sequentially add an aqueous fluorocarbon emulsion, a dispersant, a film-forming aid, a thickener, an antifoaming agent, a cosolvent, and deionized water to the primary coating in proportion. After heating to 80 °C, stir for 1 h, and then cool to room temperature to obtain the nano protective coating based on the aqueous paint.

[0023] In the above process, the dosage of each component is as follows by mass parts (it is stipulated that one unit mass part is 50 g):

[0024] The grade of the aqueous polyurethane resin is HYDRAN AP-30F; The model of the aqueous fluorocarbon emulsion is FX-970; The silane coupling agent is γ-aminopropyltriethoxysilane; The dispersant is a polyacrylate dispersant, specifically lithium polyacrylate; The film-forming aid is propylene glycol phenyl ether; The thickener is a polyurethane associative thickener, specifically RM-2020; The antifoaming agent is a silicone antifoaming agent, specifically DC-200; The cosolvent is propylene glycol; In the above process, the modified nano filler composition is a mixture of nano-silica, nano-alumina, and nano-aluminum hydroxide with a mass ratio of 5:3:2; The modified nano filler composition is prepared through the following steps: S11. Weigh 5 parts of nano-silica, 3 parts of nano-alumina, and 2 parts of nano-aluminum hydroxide by mass parts respectively, and conduct activation treatment at 200 °C for 2 h; S12. Mix 2 parts of γ-aminopropyltriethoxysilane with 90 parts of an ethanol aqueous solution with a concentration of 30% to prepare a grafting treatment solution, and control the pH of the grafting treatment solution to 4.4; S13. Sequentially immerse the activated nano-silica, nano-alumina, and nano-aluminum hydroxide into the grafting treatment solution, stir and react at 90 °C for 3 h, then centrifuge, wash, and dry to obtain a pre-modified nano filler composition; S14. Mix the pre-modified nano filler composition with 2% of triethyl phosphate by addition amount, stir and react at 70 °C for 1 h to obtain the modified nano filler composition. Repeat the above steps cyclically to prepare a large amount of modified nano filler composition, and take 15 parts for the preparation of the nano protective coating.

[0025] In the above process, the fluorocarbon-modified polysiloxane is prepared through the following steps: S21. Dissolve 10 parts of (3,3,3-trifluoropropyl)methyldichlorosilane in 50 parts of toluene, and hydrolyze at 50 °C for 2 h to form a fluorine-containing hydrolyzed homopolymer; S22. Sequentially add 8 parts of octamethylcyclotetrasiloxane, 1 part of methyltrifluoropropylcyclotrisiloxane, 0.3 part of hexamethyldisiloxane, and 0.05 part of p-toluenesulfonic acid to the fluorine-containing hydrolyzed homopolymer, and polymerize at 60 °C for 6 h to finally obtain a fluorocarbon-modified polysiloxane.

[0026] Example 3, a production process of a nano protective coating based on waterborne paint: S1. Mix waterborne polyurethane resin, fluorocarbon-modified polysiloxane, modified nano filler composition, ammonium polyphosphate, and silane coupling agent in proportion, heat to 70 °C and stir for 2 h, and cool to room temperature to obtain a primary coating; S2. Sequentially add waterborne fluorocarbon emulsion, dispersant, film-forming aid, thickener, defoamer, cosolvent, and deionized water to the primary coating in proportion, heat to 90 °C and stir for 1 h, and cool to room temperature to obtain the nano protective coating based on waterborne paint.

[0027] In the above process, each component is in parts by mass, and the dosages are as follows (it is stipulated that one unit of part by mass is 50 g):

[0028] The waterborne polyurethane resin has the brand of HYDRAN AP-30F; The waterborne fluorocarbon emulsion has the model of FX-970; The silane coupling agent is γ-methacryloxypropyltrimethoxysilane; The dispersant is a polyacrylate dispersant, specifically lithium polyacrylate; The film-forming aid is propylene glycol phenyl ether; The thickener is a polyurethane associative thickener, specifically RM-2020; The defoamer is a silicone defoamer, specifically DC-200; The cosolvent is propylene glycol; In the above process, the modified nano filler composition is a mixture of nano-silica, nano-alumina, and nano-aluminum hydroxide with a mass ratio of 5:3:2; The modified nano filler composition is prepared through the following steps: S11. Weigh 5 parts of nano-silica, 3 parts of nano-alumina, and 2 parts of nano-aluminum hydroxide by mass respectively, and perform activation treatment at 190 °C for 2 h; S12. Mix 3 parts of γ-aminopropyltriethoxysilane with 100 parts of an ethanol aqueous solution with a concentration of 35% to prepare a graft treatment solution, and control the pH of the graft treatment solution to 4.4; S13. Immerse the activated nano-silica, nano-alumina, and nano-aluminum hydroxide into the graft treatment solution in sequence, stir and react at 90 °C for 3 h, centrifuge, wash, and dry to obtain a pre-modified nano-filler composition; S14. Mix the pre-modified nano-filler composition with 2% by weight of triethyl phosphate, stir and react at 70 °C for 1 h to obtain the modified nano-filler composition. Repeat the above steps cyclically to prepare a large amount of the modified nano-filler composition, and take 12 parts for the preparation of the nano-protective coating.

[0029] In the above process, the fluorocarbon-modified polysiloxane is prepared through the following steps: S21. Dissolve 13 parts of (3,3,3-trifluoropropyl)methyldichlorosilane in 60 parts of toluene, and hydrolyze at 70 °C for 2 h to generate a fluorine-containing hydrolyzed homopolymer; S22. Add 9 parts of octamethylcyclotetrasiloxane, 1 part of methyltrifluoropropylcyclotrisiloxane, 0.5 part of hexamethyldisiloxane, and 0.1 part of p-toluenesulfonic acid to the fluorine-containing hydrolyzed homopolymer in sequence, and polymerize at 100 °C for 8 h to finally obtain the fluorocarbon-modified polysiloxane.

[0030] Comparative Example 1: The difference between Comparative Example 1 and Example 1 is only that the use of the fluorocarbon-modified polysiloxane component in the original coating formula of Example 1 is cancelled in Comparative Example 1, and the remaining steps are exactly the same in Comparative Example 1 and Example 1.

[0031] Comparative Example 2: The difference between Comparative Example 2 and Example 1 is only that the use of the modified nano-filler composition component in the original coating formula of Example 1 is cancelled in Comparative Example 2, and the remaining steps are exactly the same in Comparative Example 2 and Example 1.

[0032] Comparative Example 3: The difference between Comparative Example 3 and Example 1 is only that the use of the fluorocarbon-modified polysiloxane and modified nano-filler composition components in the original coating formula of Example 1 is cancelled in Comparative Example 3, and the remaining steps are exactly the same in Comparative Example 3 and Example 1.

[0033] Performance test: According to the standards of GB / T 9286-2021, GB / T 1732-2020, GB / T 9274-1988, GB / T 1771-2007, and GB / T 6739-2006, test the adhesion, hardness, impact resistance, acid and alkali resistance, and durability of the prepared nano-protective coating based on waterborne paint. The test results are as follows: Table 1. Summary Table of Performance Test Data of Protective Coatings

[0034] Referring to the test data in Table 1, the adhesion of a nano protective coating based on waterborne paint provided by the present invention is significantly better than that of Comparative Examples 1-3, indicating that the fluorocarbon-modified polysiloxane and the modified nano-fillers enhance the interfacial bonding between the coating and the substrate through chemical bonding (Si-O-Si / carbamate). In Comparative Example 1, the hydrophobic interfacial effect of the fluorocarbon chain is lacking, resulting in slight edge peeling. In Comparative Examples 2 and 3, the absence of nano-fillers directly leads to a decrease in the interfacial bonding strength of the composite material, greatly reducing the adhesion of the coating. The pencil hardness, impact resistance, acid and alkali resistance of Examples 1-3 are significantly higher than those of Comparative Examples 1-3. This is attributed to the high rigidity of the fluorocarbon chain and the dispersion strengthening effect of the nano-fillers in the nano protective coating prepared by the present invention. A dynamic crosslinking network can be formed through the bonding of carbamate groups and siloxane segments, and with the gradient double-fluorine modification design, the mechanical strength and hydrophobic anti-corrosion performance can be improved synchronously.

[0035] According to the standards of GB / T 2406-2008, GB / T 2408-2021, GB / T 8627-2007 (Method A), and GB / T 9978.1-2008, the fire resistance performance of the nano protective coating was tested, and the test results are as follows: Table 2. Summary Table of Fire Resistance Performance Test Data

[0036] Referring to the test data in Table 2, it can be seen that the fire resistance performance of a nano protective coating based on waterborne paint provided by Examples 1-3 of the present invention is significantly better than that of Comparative Examples 1-3, which strongly proves the excellent fire resistance performance of the nano protective coating provided by the present invention. Among them, in Example 1, ammonium polyphosphate decomposes at high temperature to generate polyphosphoric acid, catalyzing the system to form carbon, and at the same time, the nano-filler composition forms a heat insulation layer, cooperating with the thermal stability barrier of the fluorocarbon chain (decomposition temperature > 400°C), and the vertical burning grade reaches V-0 (flame self-extinguishing ≤ 10 s), with the best fire resistance performance. And in Example 1, the fluorocarbon-modified polysiloxane reduces the combustion of organic substances (F-C bonds inhibit the free radical chain reaction), and the nano-fillers adsorb some soot particles, which can also greatly reduce the smoke density and reduce the secondary damage caused by toxic smoke in the fire scene. The fire resistance performance of Example 2 is slightly lower. It is speculated that the reason is that the amount of ammonium polyphosphate is reduced and the amount of nano-fillers is decreased, resulting in insufficient compactness of the heat insulation layer and being unable to completely inhibit the flame spread. The fire resistance performance of Comparative Example 3 is the worst. The reason is that the use of fluorocarbon-modified polysiloxane and nano-fillers is cancelled, and only ammonium polyphosphate is relied on for flame retardancy, while the combustion decomposition of ammonium polyphosphate is insufficient, resulting in a significant reduction in the flame retardancy performance.

[0037] Although embodiments of the present invention have been shown and described, it will be understood by those of ordinary skill in the art that various changes, modifications, substitutions and alterations can be made to these embodiments without departing from the principles and spirit of the present invention, and the scope of the present invention is defined by the appended claims and their equivalents.

Claims

1. A nano protective coating based on waterborne paint, characterized in that, It comprises the following components by mass parts: 50 - 60 parts of waterborne polyurethane resin, 10 - 20 parts of fluorocarbon-modified polysiloxane, 14 - 23 parts of modified nano filler composition, 3 - 5 parts of ammonium polyphosphate, 10 - 12 parts of waterborne fluorocarbon emulsion, 1 - 3 parts of silane coupling agent, 1 - 2 parts of dispersant, 2 - 4 parts of film-forming aid, 1 - 2 parts of thickener, 0.5 - 1 part of defoamer, 10 - 15 parts of cosolvent, and 20 - 40 parts of deionized water.

2. The nano protective coating based on waterborne paint according to claim 1, characterized in that, The modified nano filler composition is a mixture of nano silica, nano alumina, and nano aluminum hydroxide in a mass ratio of 5:3:

2.

3. The nano protective coating based on waterborne paint according to claim 2, characterized in that, The modified nano filler composition is prepared through the following steps: S11. Weigh corresponding masses of nano silica, nano alumina, and nano aluminum hydroxide respectively according to the ratio, and conduct activation treatment at 180 - 200 °C for 2 - 3 h. S12. Mix the silane coupling agent with an ethanol aqueous solution with a concentration of 30 - 40% according to the ratio to prepare a grafting treatment solution. S13. Immerse the activated nano silica, nano alumina, and nano aluminum hydroxide into the grafting treatment solution in sequence, stir and react at 80 - 90 °C for 3 - 4 h, then centrifuge, wash, and dry to obtain a pre-modified nano filler composition. S14. Mix the pre-modified nano filler composition with 1 - 2% of triethyl phosphate by addition amount, and stir and react at 60 - 70 °C for 1 - 2 h to obtain the modified nano filler composition.

4. The nano protective coating based on waterborne paint according to claim 3, characterized in that, In step S12, the ratio of the silane coupling agent to the ethanol aqueous solution is 2 - 3:90 - 100; the pH of the grafting treatment solution is controlled at 4 - 5.

5. A nano-protective coating based on waterborne paint according to claim 4, characterized in that, In step S12, the silane coupling agent is selected from one or more of γ-aminopropyltriethoxysilane and γ-methacryloxypropyltrimethoxysilane.

6. A nano protective coating based on waterborne paint according to claim 1, characterized in that, The fluorocarbon-modified polysiloxane is prepared through the following steps: S21. Dissolve 10 - 15 parts of (3,3,3-trifluoropropyl)methyldichlorosilane by mass parts in 50 - 60 parts of toluene, and hydrolyze at 40 - 100 °C for 2 - 4 h to generate a fluorinated hydrolyzed homopolymer. S22. Add 8 - 9 parts of octamethylcyclotetrasiloxane, 1 - 2 parts of methyltrifluoropropylcyclotrisiloxane, 0.3 - 0.5 parts of hexamethyldisiloxane, and 0.01 - 0.1 parts of p-toluenesulfonic acid to the fluorinated hydrolyzed homopolymer in sequence, and polymerize at 60 - 120 °C for 6 - 12 h to finally obtain the fluorocarbon-modified polysiloxane.

7. A nano protective coating based on waterborne paint according to claim 1, characterized in that, The dispersant is a polyacrylate dispersant; the thickener is a polyurethane associative thickener; the defoamer is a silicone defoamer.

8. A nano protective coating based on waterborne paint according to claim 1, characterized in that, The cosolvent is selected from one or more of propylene glycol, ethylene glycol monobutyl ether, and dipropylene glycol methyl ether; the film-forming aid is selected from one or more of propylene glycol phenyl ether and dodecyl alcohol ester.

9. A production process of a nano-protective coating based on waterborne paint, which is used to produce the nano-protective coating according to any one of claims 1-8, characterized in that, It includes the following steps: S1. Mix the waterborne polyurethane resin, fluorocarbon-modified polysiloxane, modified nano filler composition, ammonium polyphosphate, and silane coupling agent according to the ratio, heat up to 60 - 80 °C, stir for 2 - 3 h, and cool to room temperature to obtain a primary coating. S2. Sequentially add an aqueous fluorocarbon emulsion, a dispersant, a film-forming aid, a thickener, an antifoaming agent, a cosolvent, and deionized water to the primary coating in proportion. After heating to 80 - 100 °C, stir for 1 - 2 h, and after cooling to room temperature, obtain the nano protective coating based on the aqueous paint.

10. The production process of a nano protective coating based on waterborne paint according to claim 9, characterized in that, The silane coupling agent is selected from one or more of γ-aminopropyltriethoxysilane and γ-methacryloxypropyltrimethoxysilane.

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