An aqueous self-cleaning coating

Abstract

The present invention discloses an aqueous self-cleaning coating, which is prepared by mixing raw material components such as fluorine-modified polyacrylate emulsion, reactive fluorocarbon leveling agent, thickener, defoamer, antiseptic and mildew-proof agent, etc. The aqueous self-cleaning coating has a low surface tension, good hydrophobic and oleophobic effects, and dust, carbon deposits and incompletely burned oil mists deposited on the surface of the aqueous self-cleaning coating are easy to remove, and the cleaning is convenient and the effect is good; moreover, there is no free emulsifier in the aqueous self-cleaning coating, it has good stability, a flat surface, a high light transmittance after film formation, strong adhesion in various substrates, and it also does not contain long-chain fluorinated alkanes that are difficult to degrade, and is green and environmentally friendly.

Description

Technical Field

[0001] The present invention belongs to the technical field of waterborne coatings, and particularly relates to a waterborne self-cleaning coating. Background Art

[0002] With the rapid development of China's highway industry, highways are gradually extending into mountainous areas. Due to the complex geological structure in mountainous areas, tunnels are essential in the construction of highways in mountainous areas. While the highway tunnels are developing rapidly, the traffic safety situation is severe. This is mainly because highway tunnels belong to a dark environment. When a driver enters a tunnel during the day, the light environment changes from bright to dark, which will cause the driver's vision to have a "black hole" phenomenon and make it impossible to clearly see the road surface within a short time, thus leading to traffic accidents.

[0003] In order to reduce the incidence of traffic accidents in tunnels, various lighting facilities often need to be installed in tunnels, especially to strengthen the lighting at the tunnel entrance section to relieve the visual "black hole" phenomenon of drivers and passengers and reduce the brightness difference between inside and outside the tunnel. However, pollutants such as dust, carbon deposits, and unburned oil mists carried by cars when driving at high speed in the tunnel will adhere to the lamp covers, which will greatly reduce the illuminance of the lamps, not only wasting electric energy but also posing a major safety hazard to drivers. Therefore, the lamp covers must be cleaned regularly. The lamp cover cleaning is carried out manually or by machine with water or water dissolved with detergent. Since the lamp covers are usually made of glass or plastic, the pollutants are not easily washed clean thoroughly and are likely to reattach the pollutants. Frequent cleaning not only takes time and effort but also occupies highway resources. Therefore, it is necessary to appropriately treat the lamp covers.

[0004] For such hydrophobic and oleophobic application scenarios, after extensive research by those skilled in the art, it has been found that the surface tension of fluorocarbon chains is low, and the hydrophobic and oleophobic effects are relatively good. This has attracted wide attention. Patent CN 1435434A provides an aqueous dispersion, which is formed by emulsion polymerization reaction of a fluorine-containing 1,3-diene compound with a double bond-containing compound in the presence of a surfactant with a hydrophilic-lipophilic balance value of 10 or more. The length of the fluorocarbon chain segment in the aqueous dispersion is 1-12, and a saturated fluorocarbon chain segment is particularly preferred. The aqueous dispersion can endow the surface of an article with excellent hydrophobic and oleophobic properties and excellent durability. At the same time, due to the reduction in the amount of organic solvents used, the environmental impact is small. However, due to the presence of fluorocarbon chain segments with more than 8 carbon atoms, it cannot be degraded under natural conditions and cannot be excreted from the animal body, and its long-term toxicity and environmental damage cannot be underestimated. Patent CN 102585073A discloses a fluorine-modified acrylate emulsion and its preparation method. The fluorosilicon-modified acrylate emulsion is mainly prepared from a fluorine-containing monomer, vinyltriisopropoxysilane, nano-silica sol, vinyl monomer, long-chain monomer, emulsifier, pH buffer, initiator, deionized water, etc. The fluorine element is enriched on the surface of the latex particles, giving full play to the hydrophobic and oleophobic properties of the fluorine emulsion, reducing the amount of fluorine monomer used, and reducing costs. However, the fluorine-containing monomer still has fluorocarbon groups with more than 8 carbon atoms, which is harmful to the human body and the environment. Patent CN 113667051A discloses a preparation method of a highly hydrophobic and oleophobic emulsion containing short-chain perfluoroalkyl groups. The emulsion is synthesized by miniemulsion polymerization of a short-chain perfluoropolyether monomer and an acrylic monomer in the presence of an emulsifier, a crosslinking agent and a co-stabilizer, and adding an initiator to form a monomer copolymer. The highly hydrophobic and oleophobic emulsion prepared by this method does not contain a perfluorinated long-chain alkyl structure, has the advantage of being easily degradable, is environmentally friendly, meets the requirements of green chemistry, and its coating has excellent hydrophobic and oleophobic properties on substrates such as glass, wood, steel plate, rate, etc. However, the perfluoropolyether monomer accounts for more than 30wt% of the total amount of monomers, the synthesis is complex, and the cost is extremely high; the co-stabilizers such as n-hexadecane and hexadecyl alcohol polystyrene need to be added during the preparation of the emulsion, and the co-stabilizers are lipophilic substances, which have a negative impact on the oleophobic property, and n-hexadecane is a liquid with extremely low volatility and will still exist in the dry film for a long time after the emulsion dries, affecting the performance of the paint film. Summary of the Invention

[0005] The object of the present invention is to provide an aqueous self-cleaning coating aiming at the deficiencies of the prior art. The aqueous self-cleaning coating has a low surface tension, good hydrophobic and oleophobic effects. Dust, carbon deposits and incompletely burned oil mists deposited on the surface of the aqueous self-cleaning coating can be easily removed by simple water washing, with good cleaning effect and convenience; and it does not contain free emulsifiers, has good stability, a flat surface, high light transmittance after film formation, and strong adhesion in various substrates; it does not contain long-chain fluoroalkanes that are difficult to degrade, and is green and environmentally friendly.

[0006] To achieve the above object, the present invention adopts the following technical solutions:

[0007] A waterborne self-cleaning coating, in parts by weight, the components and their amounts used are 560 - 650 parts of fluorine-modified polyacrylate emulsion, 275 - 357 parts of deionized water, 35 - 41 parts of film-forming aid, 5 - 10 parts of thickener, 1 - 2 parts of defoamer, 25 - 30 parts of reactive fluorocarbon leveling agent, 1 - 2 parts of antiseptic and mildew-proof agent, and 0 - 3 parts of concentrated ammonia water (purity 25wt%).

[0008] Furthermore, the fluorine-modified polyacrylate emulsion is prepared by first preparing a core polymer from acrylate monomers and hydrophilic monomers through emulsion polymerization in the presence of an emulsifier, then dropping a mixed monomer solution of perfluoro polyether acrylate, acrylate monomers, functional monomers, and hydrophilic monomers to prepare the shell layer, and then adding a small amount of stabilizer and hydrazide compound as a later cross-linking supplement to further improve its performance; the preparation steps are as follows:

[0009] 1) In parts by weight, dissolve 5 - 8 parts of reactive anionic emulsifier in 180 - 210 parts of deionized water, dropwise add a mixed monomer composed of 130 - 160 parts of acrylate soft monomer, 135 - 175 parts of acrylate hard monomer, and 2 - 3 parts of hydrophilic monomer, and stir at 600 - 800 rpm for 0.5 - 1 hour to obtain pre-emulsion A;

[0010] 2) Dissolve 7 - 10 parts of reactive anionic emulsifier and 3 - 6 parts of reactive nonionic emulsifier in 100 - 130 parts of deionized water, dropwise add a mixed monomer composed of 85 - 105 parts of perfluoro polyether acrylate, 30 - 50 parts of acrylate soft monomer, 45 - 60 parts of acrylate hard monomer, 12 - 19 parts of functional monomer, and 2 - 4 parts of itaconic acid, and stir at 600 - 800 rpm for 0.5 - 1 hour to obtain pre-emulsion B;

[0011] 3) Take 150 - 250 parts of deionized water, add 5 - 8 parts of reactive anionic emulsifier, 2 - 4 parts of reactive nonionic emulsifier, and 1 - 2 parts of waterborne initiator, stir evenly and heat up to 70 - 90 °C, then add 10 - 15wt% of the pre-emulsion A prepared in step 1), react for 0.3 - 0.5 hours, and then simultaneously drop the remaining pre-emulsion A and an initiator aqueous solution containing 1 - 1.5 parts of waterborne initiator in 30 parts, and the dropping lasts for 2 - 3 hours; after the dropping of pre-emulsion A is completed, continue to simultaneously drop pre-emulsion B and an initiator aqueous solution containing 0.8 - 1.2 parts of waterborne initiator in 20 parts, and the dropping lasts for 1 - 2 hours. After the dropping is completed, continue to keep the temperature for 2 - 3 hours, then cool down to 20 - 30 °C, adjust the pH = 7 - 9 with concentrated ammonia water (purity 25wt%), then add 3 - 5 parts of stabilizer and 6 - 10 parts of hydrazide compound, and filter through a 500-mesh sieve to remove gels to obtain the fluorine-modified polyacrylate emulsion.

[0012] Further, the reactive anionic emulsifier is allyl polyoxyethylene ether ammonium sulfate.

[0013] The reactive nonionic emulsifier is one of allyl polyglycol ether APEG-500, APEG-700, and APEG800.

[0014] The perfluoro polyether acrylate is selected from perfluoro polyether methacrylate (PFPE-MAA-1000, whose structural formula is CH2=C(CH3)COOCH2[OCF(CF3)CF2] n OH, n = 4 - 6, and the average molecular weight is 1000 Da) or perfluoro polyether acrylate (PFPE-AA-1000, whose structural formula is CH2=CHCOOCH2[OCF(CF3)CF2] n OH, n = 4 - 6, and the average molecular weight is 1000 Da).

[0015] The acrylate soft monomer is one or more of butyl acrylate, butyl methacrylate, isooctyl acrylate, and lauryl acrylate.

[0016] The acrylate hard monomer is one or more of methyl acrylate, methyl methacrylate, isobornyl acrylate, and isobornyl methacrylate.

[0017] The hydrophilic monomer is one of acrylic acid and methacrylic acid.

[0018] The functional monomer is ethyl acetoacetoxy methacrylate (CAS No.: 21282-97-3).

[0019] The aqueous initiator is one of potassium persulfate, ammonium persulfate, and sodium persulfate.

[0020] The stabilizer is BY-9,550.

[0021] The hydrazide compound is one of adipic dihydrazide, succinic dihydrazide, and glutaric dihydrazide.

[0022] Furthermore, the reactive fluorocarbon leveling agent is first prepared by subjecting polyhexafluoroepoxypropane monomethanol to a halogenation reaction with hydroiodic acid in the presence of phosphoric acid and a phase transfer catalyst to generate iodomethylenepolyhexafluoroepoxypropane. Then, iodomethylenepolyhexafluoroepoxypropane, a fluorinated alcohol, and carbon disulfide are heated and reacted in a basic condition and in a tetrahydrofuran solvent to obtain a fluorinated alkyl xanthate perfluoropolyether ester. Then, using the fluorinated alkyl xanthate perfluoropolyether ester as a chain transfer agent, acrylate monomers, hydrophilic monomers, and glycidyl methacrylate are subjected to a polymerization reaction in a solvent to obtain a polymer with a certain molecular weight and molecular weight distribution. Then, isophorone diamine reacts with the epoxy groups in the polymer to generate an amino-containing reactive fluorocarbon leveling agent. The preparation steps are as follows:

[0023] a) By weight, 1000 parts of polyhexafluoroepoxypropane monomethanol, 440 - 460 parts of 55 wt% aqueous hydroiodic acid solution, 100 - 120 parts of phosphoric acid (purity 85 wt%), and 80 - 100 parts of the phase transfer catalyst tetrabutylammonium iodide are mixed, heated to 110 - 120 °C, reacted for 4 - 7 hours, then cooled to 30 - 40 °C, allowed to stand for layering to remove the aqueous layer, and then the organic layer is washed 3 times with 1000 parts of deionized water to remove the aqueous layer, obtaining a transparent solution;

[0024] b) 16.8 - 23.6 parts of a fluorinated alcohol are dissolved in 60 - 72 parts of tetrahydrofuran, 2.52 - 6.16 parts of a base are added, heated to 40 - 55 °C, reacted for 6 - 10 hours, and then cooled to 35 - 40 °C; 15.2 - 18.3 parts of carbon disulfide are dropwise added thereto within 0.5 - 1 hour, reacted at 35 - 40 °C for 2 - 5 hours, and then tetrahydrofuran and excess carbon disulfide are removed by vacuum distillation; 120 - 145 parts of tetrahydrofuran and 260 - 295 parts of the transparent solution obtained in step 1) are added, stirred at 45 - 55 °C for 16 - 24 hours, tetrahydrofuran is removed by vacuum distillation, and recrystallized with ethanol to obtain the chain transfer agent fluorinated alkyl xanthate perfluoropolyether ester;

[0025] c) Add 37.2 - 42.6 parts of perfluoroalkyl xanthate perfluoropolyether ester, 10 - 22 parts of acrylate soft monomer, 125 - 140 parts of solvent, and 0.48 - 0.73 parts of oil-soluble initiator into a reaction kettle. After stirring evenly, heat it to 65 - 75°C under nitrogen protection. After reacting for 0.5 hours, dropwise add a mixed monomer composed of 30 - 47 parts of acrylate soft monomer, 42 - 60 parts of acrylate hard monomer, 10 - 14 parts of glycidyl methacrylate, and 3 - 4 parts of hydrophilic monomer within 2 - 3 hours. Continue to keep the temperature for reaction for 4 - 6 hours, then cool down to 30 - 40°C; adjust the pH to 8 - 9 with ammonia water, then slowly add 12 - 16.8 parts of isophorone diamine, stir and heat up to 55 - 65°C, react for 4 - 7 hours, then cool down to 20 - 30°C, add 20 - 25 parts of deionized water, stir and dissolve evenly to obtain the reaction-type fluorocarbon leveling agent.

[0026] Further, the structural formula of the polyhexafluoroepoxypropane monomethanol is [CF(CF3)CF2O] m CH2OH (CAS No.: 90317 - 77 - 4), its average molecular weight is 1000 Da, and the purity ≥ 97.5%.

[0027] The fluorinated alcohol is one of perfluorotert-butanol (CAS No.: 2378 - 02 - 1), hexafluoroisopropanol (CAS No.: 920 - 66 - 1), 2,2,3,3,4,4,4 - heptafluorobutanol - 1 (CAS No.: 375 - 01 - 9).

[0028] The base is one of potassium hydroxide, sodium hydroxide, and lithium hydroxide.

[0029] The acrylate soft monomer is one or more of butyl acrylate, butyl methacrylate, isooctyl acrylate, and lauryl acrylate.

[0030] The acrylate hard monomer is one or more of methyl acrylate, methyl methacrylate, isobornyl acrylate, and isobornyl methacrylate.

[0031] The hydrophilic monomer is one of acrylic acid and methacrylic acid.

[0032] The solvent is propylene glycol dimethyl ether or dipropylene glycol dimethyl ether.

[0033] The oil-soluble initiator is azobisisobutyronitrile or azobisisoheptonitrile.

[0034] Further, the film-forming aid is one of Eastman Texanol, Dow Chemical Dowanol® DPnB, and Dow Chemical Dowanol® DPM.

[0035] Further, the thickener is one or more of Wanhua Chemical's Vesmody® A406, Vesmody® A408, Vesmody® U601, and Vesmody® U902.

[0036] Further, the defoamer is one or more of Degussa Tego Foamex 825, Tego Foamex 810, and Tego Foamex 1488.

[0037] Further, the antiseptic and mildew-proof agent is one of Dow Chemical's Kathon® LXE and Rocima® 631.

[0038] Further, the preparation of the waterborne self-cleaning coating is to mix the fluorine-modified polyacrylate emulsion, deionized water, film-forming aid, thickener, defoamer, reactive fluorocarbon leveling agent, antiseptic and mildew-proof agent, and concentrated ammonia water in proportion, stir at 600 - 800 rpm for 0.5 - 1 hour, and then filter through a 500-mesh filter to remove gels.

[0039] The obtained waterborne self-cleaning coating is used on the surface of lighting equipment.

[0040] The beneficial effects of the present invention are as follows:

[0041] a) The fluorine-modified polyacrylate emulsion prepared in the present invention has a pH close to neutral and contains a large amount of water. The hydrazide group of the amine group and hydrazide compound in the reactive fluorocarbon leveling agent has weak activity and basically does not react with acetoacetoxyethyl methacrylate. After adding the stabilizer BY-9550, the performance of the emulsion state can be maintained stable and unchanged in color for a long time; during the drying process of the emulsion, as the water and the neutralizing agent ammonia volatilize, the pH of the system decreases, and the amine group in the reactive fluorocarbon leveling agent can undergo a dehydration reaction with the carbonyl group of acetoacetoxyethyl methacrylate to fix the fluorinated chain segment on the coating surface and form a regular structure, reducing the surface tension of the coating surface and improving the hydrophobic and oleophobic properties of the coating; at the same time, the hydrazide group of the hydrazide compound can undergo a crosslinking reaction with the carbonyl group of acetoacetoxyethyl methacrylate to improve the mechanical and weather resistance of the coating film.

[0042] b) The surface of the latex particles of the fluorine-modified polyacrylate emulsion prepared in the present invention contains perfluoropolyether chain segments and has a low surface tension. Due to the Benard effect during the film-forming process, phenomena such as orange peel may occur. When used in combination with the reactive fluorocarbon leveling agent, since the fluidity of the reactive fluorocarbon leveling agent is better than that of the latex particles of the fluorine-modified polyacrylate emulsion, during the film-forming process, the reactive fluorocarbon leveling agent can quickly migrate to the parts with high surface tension, filling the defect that the latex particles of the fluorine-modified polyacrylate emulsion cannot flow quickly due to the increase in viscosity, reducing the surface tension difference between different parts during the film-forming process, suppressing the Benard effect on the coating surface, obtaining a flat surface, and being beneficial to light transmission through the coating.

[0043] c) Since conventional emulsifiers may affect the hydrophobic and oleophobic properties of the paint film, the waterborne self-cleaning coating of the present invention uses reactive anionic emulsifiers and reactive nonionic emulsifiers. After the polymerization is completed, there is basically no free emulsifier in the system. Moreover, after copolymerizing with high refractive index monomers such as isobornyl acrylate or isobornyl methacrylate, it has good stability, high light transmittance after drying into a film, and strong adhesion to various substrates.

[0044] d) In the preparation process of the reactive fluorocarbon leveling agent and the fluorine-modified polyacrylate emulsion of the present invention, degradable perfluoropolyether chains are selected, which have little impact on the environment. And the fluorine-modified polyacrylate emulsion adopts the core-shell structure preparation technology, and basically does not contain perfluoropolyether chain segments inside, which is beneficial to improving the stability of the emulsion, reducing the dosage of perfluoropolyether, and having a relatively low cost. Its preparation process is similar to that of conventional polyacrylate coatings and is suitable for large-scale production. Description of the Drawings

[0045] Figure 1 It is the infrared spectrum of the fluorine-modified polyacrylate emulsion prepared in Example 1; in the figure, 1149 cm -1 is the characteristic absorption peak of the C-O-C bond of perfluoropolyether, and 1246 cm -1 is the characteristic absorption peak of CF2 and CF3; 1738 cm -1 is the characteristic absorption peak of the carbonyl group of acrylate, 1376 cm -1 , 1463 cm -1 , 2852 cm -1 , 2923 cm -1 , 2956 cm -1 are the characteristic absorption peaks of CH3 and CH2, and 723 cm -1 is the characteristic absorption peak of a straight-chain alkyl group with a carbon atom number ≥ 4. The above absorption peaks indicate the successful preparation of the fluorine-modified polyacrylate emulsion.

[0046] Figure 2 It is the infrared spectrum of hexafluoroisopropyl xanthate perfluoropolyether ester prepared in Example 1; in the figure, 1149 cm -1 is the characteristic absorption peak of the C-O-C bond of perfluoropolyether, 1246 cm -1 is the characteristic absorption peak of CF2 and CF3, 1225 cm -1 , 1076 cm -1 , 1031 cm -1 , 684 cm -1 are the characteristic absorption peaks of the C=S and C-S bonds of the xanthate group. These characteristic peaks indicate the successful preparation of hexafluoroisopropyl xanthate perfluoropolyether ester.

[0047] Figure 3Infrared spectrum of the reactive fluorocarbon leveling agent prepared in Example 1; in the figure, 3350 cm -1 , 1620 cm -1 is the characteristic absorption peak of the amino N-H bond; 1149 cm -1 is the characteristic absorption peak of the C-O-C bond of perfluoropolyether, 1246 cm -1 is the characteristic absorption peak of CF2 and CF3; 1737 cm -1 is the characteristic absorption peak of the carbonyl group of acrylate, 1697 cm -1 is the characteristic absorption peak of the carboxylic acid carbonyl group; 1376 cm -1 , 1463 cm -1 , 2852 cm -1 , 2923 cm -1 , 2956 cm -1 are the characteristic absorption peaks of CH3 and CH2, 723 cm -1 is the characteristic absorption peak of a straight-chain alkyl group with a carbon atom number ≥ 4. The above absorption peaks indicate the successful preparation of the reactive fluorocarbon leveling agent.

[0048] Figure 4 shows the states of water and diesel on the surface of the waterborne self-cleaning coating and the uncoated glass prepared in Example 1 (the colorless and transparent liquid on the upper part is water, and the yellow and transparent liquid on the lower part is diesel). Detailed implementation manners

[0049] To make the content of the present invention easier to understand, the technical solutions of the present invention will be further described below in conjunction with specific implementation manners, but the present invention is not limited thereto.

[0050] PFPE-MAA-1000 and PFPE-AA-1000 used were purchased from Suzhou Cangmu New Materials Co., Ltd. The stabilizer BY-9550 used was purchased from Beijing Baiyuan Chemical Co., Ltd. The polyhexafluoroepoxypropane monomethanol used was purchased from Sanming Haisifu Chemical Technology Co., Ltd.

[0051] Example 1

[0052] The preparation steps of a waterborne self-cleaning coating are as follows:

[0053] Step (1): Dissolve 5 g of allyl polyoxyethylene ether ammonium sulfate in 180 g of deionized water, and dropwise add a mixed monomer composed of 130 g of isooctyl acrylate, 135 g of methyl methacrylate, and 2 g of acrylic acid, and stir at 800 rpm for 0.5 hour to obtain pre-emulsion A;

[0054] Dissolve 7 g of allyl polyoxyethylene ether ammonium sulfate and 3 g of APEG-500 in 100 g of deionized water, and dropwise add a mixed monomer composed of 90 g of PFPE-MAA-1000, 20 g of butyl acrylate, 12 g of isooctyl acrylate, 48 g of methyl acrylate, 10 g of isobornyl methacrylate, 12 g of acetoacetoxyethyl methacrylate and 2 g of itaconic acid, and stir at 600 rpm for 1 hour to obtain pre-emulsion B;

[0055] Take 220 g of deionized water, add 5 g of allyl polyoxyethylene ether ammonium sulfate, 3 g of APEG-500 and 1.5 g of potassium persulfate, stir evenly and heat up to 90 °C, add 45 g of pre-emulsion A, after reacting for 0.3 hours, simultaneously dropwise add the remaining pre-emulsion A and 30 g of aqueous solution dissolved with 1 g of potassium persulfate, and the dropping lasts for 2 hours; after the dropping of pre-emulsion A is completed, continue to dropwise add pre-emulsion B and 20 g of aqueous solution dissolved with 1.1 g of potassium persulfate, and the dropping lasts for 1 hour, after the dropping is completed, continue to keep warm for 2 hours, cool down to 30 °C, adjust the pH = 9 with 25 wt% concentrated ammonia water, add 5 g of stabilizer BY-9550 and 6 g of succinic dihydrazide, and filter through a 500-mesh filter to remove the gel to obtain a fluorine-modified polyacrylate emulsion.

[0056] Step (2): Heat 1000 g of polyhexafluoroepoxypropane monomethanol, 440 g of 55 wt% hydroiodic acid aqueous solution, 100 g of 85 wt% phosphoric acid and 80 g of phase transfer catalyst tetrabutylammonium iodide to 120 °C, after reacting for 4 hours, cool down to 30 °C, let it stand and separate layers to remove the aqueous solution layer, wash the organic layer 3 times with 1000 g of deionized water, remove the aqueous solution layer to obtain a transparent solution;

[0057] Dissolve 16.8 g of hexafluoroisopropanol in 60 g of tetrahydrofuran, add 2.52 g of lithium hydroxide, heat to 40 °C and react for 10 hours, cool to 35 °C; dropwise add 15.2 g of carbon disulfide within 0.5 hours, after reacting at 35 °C for 5 hours, distill off tetrahydrofuran and excess carbon disulfide under reduced pressure; then add 120 g of tetrahydrofuran and 260 g of the obtained transparent solution, stir at 55 °C for 16 hours, distill off tetrahydrofuran under reduced pressure, and recrystallize with ethanol to obtain a chain transfer agent hexafluoroisopropyl xanthate perfluoropolyether ester.

[0058] Add 37.2 g of perfluoropolyether ester of hexafluoroisopropyl xanthate, 10 g of butyl acrylate, 125 g of dipropylene glycol dimethyl ether and 0.48 g of azobisisobutyronitrile into a reaction kettle. After stirring evenly, heat up to 75 °C under nitrogen protection. After reacting for 0.5 hours, dropwise add a mixed monomer composed of 27 g of butyl acrylate, 20 g of isooctyl acrylate, 50 g of methyl acrylate, 10 g of isobornyl acrylate, 14 parts of glycidyl methacrylate and 3 g of methacrylic acid within 3 hours. Continue to keep the temperature for reaction for 4 hours, then cool down to 30 °C, adjust the pH to 8.5 with ammonia water, slowly add 17.2 g of isophorone diamine, stir and heat up to 55 °C. After reacting for 7 hours, cool down to 20 - 30 °C, add 20 g of deionized water, stir and dissolve evenly to obtain a reactive fluorocarbon leveling agent.

[0059] Step (3): Add 580 g of fluorine-modified polyacrylate emulsion, 350 g of deionized water, 35 g of Texanol, 5 g of Vesmody® A406, 1 g of Tego Foamex 825, 25 g of reactive fluorocarbon leveling agent, 2 g of Rocima® 631 into the kettle. Add 2 g of 25 wt% concentrated ammonia water, stir at 600 rpm for 1 hour, then filter through a 500-mesh filter to remove gels and lumps to obtain the waterborne self-cleaning coating T1.

[0060] Example 2

[0061] The preparation steps of a waterborne self-cleaning coating are as follows:

[0062] Step (1): Dissolve 8 g of allyl polyoxyethylene ether ammonium sulfate in 210 g of deionized water, dropwise add a mixed monomer composed of 140 g of butyl acrylate, 160 g of methyl methacrylate and 3 g of methacrylic acid, and stir at 600 rpm for 1 hour to obtain pre-emulsion A;

[0063] Dissolve 10 g of allyl polyoxyethylene ether ammonium sulfate and 6 g of APEG-700 in 120 g of deionized water, dropwise add a mixed monomer composed of 105 g of PFPE-AA-1000, 30 g of butyl acrylate, 8 g of isooctyl acrylate, 38 g of methyl methacrylate, 7 g of isobornyl acrylate, 14 g of acetoacetoxyethyl methacrylate and 2 g of itaconic acid, and stir at 600 rpm for 1 hour to obtain pre-emulsion B;

[0064] Take 150 g of deionized water, add 8 g of allyl polyoxyethylene ether ammonium sulfate, 3 g of APEG-700 and 1 g of sodium persulfate, stir evenly and heat up to 70 °C, add 15 wt% of the prepared pre-emulsion A, after reacting for 0.5 hours, simultaneously drop in the remaining pre-emulsion A and 30 g of aqueous solution dissolved with 1.3 g of sodium persulfate, and the dropping lasts for 3 hours; after the dropping of pre-emulsion A is completed, continue to drop in pre-emulsion B and 20 g of aqueous solution dissolved with 1 g of sodium persulfate, the dropping lasts for 2 hours, after the dropping is completed, continue to keep the temperature for 3 hours, cool down to 25 °C, adjust the pH = 7 with 25 wt% concentrated ammonia water, add 3 g of stabilizer BY-9550 and 10 g of adipic dihydrazide, filter through a 500-mesh filter to remove gels, and obtain the fluorine-modified polyacrylate emulsion.

[0065] Step (2): Heat 1000 g of polyhexafluoropropylene oxide monomethanol, 460 g of 55 wt% hydroiodic acid aqueous solution, 120 g of 85 wt% phosphoric acid and 100 g of phase transfer catalyst tetrabutylammonium iodide to 110 °C, after reacting for 7 hours, cool down to 40 °C, let it stand and separate layers to remove the aqueous solution layer, wash the organic layer 3 times with 1000 g of deionized water, remove the aqueous solution layer, and obtain a transparent solution;

[0066] Dissolve 23.6 g of perfluorotert-butyl alcohol in 72 g of tetrahydrofuran, add 6.16 g of potassium hydroxide, heat to 55 °C and react for 6 hours, cool to 40 °C; drop 18.3 g of carbon disulfide into it within 0.5 hours, after reacting at 40 °C for 2 hours, distill off tetrahydrofuran and excess carbon disulfide under reduced pressure; then add 145 g of tetrahydrofuran and 295 g of the obtained transparent solution, stir at 45 °C for 24 hours, distill off tetrahydrofuran under reduced pressure, and recrystallize with ethanol to obtain the chain transfer agent perfluorotert-butyl xanthate perfluoropolyether ester.

[0067] Add 42.6 g of perfluorotert-butyl xanthate perfluoropolyether ester, 14 g of butyl acrylate, 8 g of lauryl acrylate, 140 g of dipropylene glycol dimethyl ether and 0.55 g of azodiisooctanenitrile into the reaction kettle, stir evenly, heat up to 65 °C under nitrogen protection, after reacting for 0.5 hours, drop in a mixed monomer composed of 17 g of butyl acrylate, 13 g of isooctyl acrylate, 24 g of methyl acrylate, 18 g of methyl methacrylate, 10 g of glycidyl methacrylate and 4 g of methacrylic acid within 2 hours, continue to keep the temperature and react for 6 hours, then cool down to 35 °C, adjust the pH = 9 with ammonia water, slowly add 12.5 g of isophorone diamine, stir and heat up to 65 °C, after reacting for 4 hours, cool down to 20 - 30 °C, add 25 g of deionized water, stir and dissolve evenly to obtain the reactive fluorocarbon leveling agent.

[0068] Step (3): Add 560 g of fluorine-modified polyacrylate emulsion, 357 g of deionized water, 41 g of Dowanol® DPM, 10 g of Vesmody® U601, 2 g of Tego Foamex 810, 28 g of reactive fluorocarbon leveling agent, and 2 g of Kathon® LXE into the kettle, stir at 800 rpm for 0.5 hour, and filter through a 500-mesh filter screen to remove gels and lumps, obtaining the waterborne self-cleaning coating T2.

[0069] Example 3

[0070] The preparation steps of a waterborne self-cleaning coating are as follows:

[0071] Step (1): Dissolve 7 g of allyl polyoxyethylene ether ammonium sulfate in 200 g of deionized water, and dropwise add a mixed monomer composed of 50 g of isooctyl acrylate, 100 g of butyl methacrylate, 160 g of methyl acrylate, and 3 g of acrylic acid, and stir at 700 rpm for 1 hour to obtain pre-emulsion A;

[0072] Dissolve 8 g of allyl polyoxyethylene ether ammonium sulfate and 4 g of APEG-500 in 130 g of deionized water, and dropwise add a mixed monomer composed of 98 g of PFPE-MAA-1000, 25 g of butyl acrylate, 25 g of isooctyl acrylate, 44 g of methyl methacrylate, 16 g of isobornyl methacrylate, 19 g of acetoacetoxyethyl methacrylate, and 4 g of itaconic acid, and stir at 700 rpm for 1 hour to obtain pre-emulsion B;

[0073] Take 250 g of deionized water, add 7 g of allyl polyoxyethylene ether ammonium sulfate, 4 g of APEG-500, and 2 g of ammonium persulfate, stir evenly and heat up to 80 °C, add 13 wt% of the prepared pre-emulsion A, react for 0.5 hour, then simultaneously dropwise add the remaining pre-emulsion A and 30 g of an aqueous solution dissolved with 1 g of ammonium persulfate, and the dropping lasts for 2.5 hours; after the dropping of pre-emulsion A is completed, continue to dropwise add pre-emulsion B and 20 g of an aqueous solution dissolved with 0.8 g of ammonium persulfate, and the dropping lasts for 2 hours. After the dropping is completed, continue to keep warm for 2.5 hours, cool down to 25 °C, adjust the pH = 8 with 25 wt% concentrated ammonia water, add 4 g of stabilizer BY-9550 and 8 g of glutaric dihydrazide, and filter through a 500-mesh filter screen to remove gels, obtaining the fluorine-modified polyacrylate emulsion.

[0074] Step (2): Add 1000 g of polyhexafluoropropylene oxide monomethanol, 450 g of 55 wt% hydroiodic acid aqueous solution, 115 g of 85 wt% phosphoric acid, and 90 g of phase transfer catalyst tetrabutylammonium iodide, heat up to 115 °C, react for 5 hours, then cool down to 40 °C, let it stand for stratification to remove the aqueous solution layer, wash the organic layer 3 times with 1000 g of deionized water, and remove the aqueous solution layer to obtain a transparent solution;

[0075] Dissolve 20 g of 2,2,3,3,4,4,4 - heptafluoro - 1 - butanol in 66 g of tetrahydrofuran, add 4.4 g of sodium hydroxide, heat to 50 °C and react for 7 hours, then cool to 38 °C; dropwise add 17 g of carbon disulfide thereto within 0.5 hours, after reacting at 38 °C for 3 hours, remove tetrahydrofuran and excess carbon disulfide by vacuum distillation; then add 132 g of tetrahydrofuran and 280 g of the obtained transparent solution, stir at 50 °C for 20 hours, remove tetrahydrofuran by vacuum distillation, and recrystallize with ethanol to obtain the chain transfer agent heptafluorobutyl xanthate perfluoropolyether ester.

[0076] Add 40 g of heptafluorobutyl xanthate perfluoropolyether ester, 16 g of butyl methacrylate, 120 g of propylene glycol dimethyl ether and 0.60 g of azobisisobutyronitrile to a reaction kettle, stir evenly, then heat to 70 °C under nitrogen protection, after reacting for 0.5 hours, dropwise add a mixed monomer composed of 18 g of butyl acrylate, 20 g of lauryl acrylate, 30 g of methyl methacrylate, 19 g of isobornyl methacrylate, 12 g of glycidyl methacrylate and 3 g of acrylic acid thereto within 2 hours, continue to keep the temperature for reaction for 5 hours, then cool to 35 °C, adjust the pH = 8 with ammonia water, slowly add 14.8 g of isophorone diamine, stir and heat to 58 °C, after reacting for 6 hours, cool to 30 °C, add 23 g of deionized water, stir and dissolve evenly to obtain a reactive fluorocarbon leveling agent.

[0077] Step (3): Mix 600 g of fluorine - modified polyacrylate emulsion, 317 g of deionized water, 39 g of Dowanol® DPnB, 7 g of Vesmody® A408, 2 g of Tego Foamex 825, 30 g of reactive fluorocarbon leveling agent, 2 g of Rocima® 631 and 3 g of 25 wt% concentrated ammonia water, stir at 700 rpm for 1 hour, filter through a 500 - mesh filter to remove gels, and obtain the water - borne self - cleaning coating T3.

[0078] Example 4

[0079] The preparation steps of a water - borne self - cleaning coating are as follows:

[0080] Step (1): Dissolve 6 g of allyl polyoxyethylene ether ammonium sulfate in 190 g of deionized water, dropwise add a mixed monomer composed of 130 g of isooctyl acrylate, 175 g of methyl acrylate and 2 g of methacrylic acid, and stir at 600 rpm for 1 hour to obtain pre - emulsion A;

[0081] Dissolve 9 g of allyl polyoxyethylene ether ammonium sulfate and 5 g of APEG800 in 110 g of deionized water, and dropwise add a mixed monomer composed of 85 g of PFPE-AA-1000, 30 g of butyl methacrylate, 13 g of isobornyl acrylate, 40 g of methyl methacrylate, 15 g of methyl acrylate, 16 g of acetoacetoxyethyl methacrylate and 3 g of itaconic acid, and stir at 600 rpm for 1 hour to obtain pre-emulsion B;

[0082] Take 240 g of deionized water, add 8 g of allyl polyoxyethylene ether ammonium sulfate, 2 g of APEG800 and 1.7 g of potassium persulfate, stir evenly and heat up to 75 °C, add 10 wt% of pre-emulsion A, and after reacting for 0.5 hours, simultaneously dropwise add the remaining pre-emulsion A and 30 g of aqueous solution dissolved with 1.5 g of potassium persulfate, and the dropping lasts for 2 hours; after the dropping of pre-emulsion A is completed, continue to dropwise add pre-emulsion B and 20 g of aqueous solution dissolved with 1.2 g of potassium persulfate, and the dropping lasts for 2 hours. After the dropping is completed, continue to keep the temperature for 3 hours, cool down to 25 °C, adjust the pH = 7.5 with 25 wt% concentrated ammonia water, add 5 g of stabilizer BY-9550 and 7 g of adipic dihydrazide, and filter through a 500-mesh filter to remove the gel to obtain the fluorine-modified polyacrylate emulsion.

[0083] Step (2): Heat 1000 g of polyhexafluoroepoxypropane monomethanol, 440 g of 55 wt% aqueous solution of hydroiodic acid, 120 g of 85 wt% phosphoric acid and 100 g of phase transfer catalyst tetrabutylammonium iodide to 110 °C, react for 7 hours, then cool down to 32 °C, let it stand and separate layers to remove the aqueous solution layer, wash the organic layer 3 times with 1000 g of deionized water, and remove the aqueous solution layer to obtain a transparent solution;

[0084] Dissolve 16.8 g of hexafluoroisopropanol in 60 g of tetrahydrofuran, add 4.2 g of sodium hydroxide, heat to 45 °C and react for 9 hours, then cool to 36 °C; dropwise add 16 g of carbon disulfide into it within 0.5 hours, react at 36 °C for 4 hours, and then distill off tetrahydrofuran and excess carbon disulfide under reduced pressure; then add 140 g of tetrahydrofuran and 270 g of the obtained transparent solution, stir at 45 °C for 24 hours, distill off tetrahydrofuran under reduced pressure, and recrystallize with ethanol to obtain the chain transfer agent hexafluoroisopropyl xanthate perfluoropolyether ester.

[0085] Add 38 g of perfluoropolyether ester of hexafluoroisopropyl xanthate, 8 g of butyl methacrylate, 8 g of lauryl acrylate, 140 g of propylene glycol dimethyl ether and 0.73 g of 2,2'-azobis(2,4-dimethylvaleronitrile) into a reaction kettle. After stirring evenly, heat up to 68 °C under nitrogen protection. After reacting for 0.5 h, dropwise add a mixed monomer composed of 12 g of butyl acrylate, 30 g of isooctyl acrylate, 27 g of methyl acrylate, 28 g of isobornyl methacrylate, 11 g of glycidyl methacrylate and 4 g of methacrylic acid within 3 h. Continue to keep the temperature for reaction for 5 h, then cool down to 35 °C, adjust the pH to 8 with ammonia water, slowly add 13.8 g of isophorone diamine, stir and heat up to 60 °C. After reacting for 5 h, cool down to 25 °C, add 25 g of deionized water, stir and dissolve evenly to obtain a reactive fluorocarbon leveling agent.

[0086] Step (3): Mix 650 g of fluorine-modified polyacrylate emulsion, 275 g of deionized water, 40 g of Texanol, 5 g of Vesmody® U902, 1 g of Tego Foamex 810, 27 g of reactive fluorocarbon leveling agent, and 2 g of Kathon® LXE, stir at 800 rpm for 0.5 h, and filter through a 500-mesh sieve to remove gels to obtain the waterborne self-cleaning coating T4.

[0087] Application Example 1

[0088] Spray the waterborne self-cleaning coatings T1-T4 prepared in the examples evenly on the surfaces of glass, polypropylene plate, PET sheet, stainless steel plate, and galvanized steel plate respectively, and conduct an adhesion test after drying at room temperature for 7 days. The adhesion test is carried out according to the "Standard Test Method ASTM D3359-09 Measurement of Adhesion by Tape Method". Check the paint film with a magnifying glass for illumination, and evaluate the grade according to the relationship between the paint stripping part and the grid area as follows:

[0089] 5B: The cut edge is very smooth and none of the grid squares peel off.

[0090] 4B: At the grid cut-in point, there is slight flaky paint film peeling off, and the affected area is 5%;

[0091] 3B: The paint layer peels off along the cut-in point or there is partial or complete peeling off at the cut-in point of the grid line, and the affected area is 5%-15%;

[0092] 2B: The paint layer peels off in large pieces or completely along the cut-in point or the grid squares peel off partially or completely. The affected area is 15-35%;

[0093] 1B: The paint layer peels off in large pieces or completely along the cut-in point or the grid squares peel off partially or completely, and the affected area is 35-65%;

[0094] 0B: The peeling area is greater than 65%.

[0095] The test results are shown in Table 1.

[0096] Table 1 Adhesion test results of waterborne self-cleaning coatings

[0097]

[0098] The results in Table 1 show that the adhesions of waterborne self-cleaning coatings T1 - T4 on various smooth surfaces are all good. Only the adhesions of T2 and T3 on polypropylene plates are 4B, and the rest are 5B, indicating that the waterborne self-cleaning coatings of the present invention have a wide application range and good adhesions on various materials.

[0099] Application Example 2

[0100] The waterborne self-cleaning coating T1 prepared in Example 1 was evenly sprayed on glass and subjected to hydrophobic and oleophobic tests after drying at room temperature for 7 days, with clean ordinary glass as a comparison. The specific operation was to add water and diesel to the surface of the coating formed by the waterborne self-cleaning coating T1 or the glass surface without coating respectively, and use an appropriate tool to level the water and diesel. After waiting for one minute, observe the states of water and diesel on the substrate surface. The results are as Figure 4 shown.

[0101] As Figure 4 can be seen, the water and diesel on the coating formed by the waterborne self-cleaning coating can automatically shrink into better droplets after being leveled, while the water and diesel on the glass surface without coating do not shrink, indicating that the coating formed by the waterborne self-cleaning coating of the present invention has good hydrophobic and oleophobic cleaning effects.

[0102] The above are only the preferred embodiments of the present invention. All equivalent changes and modifications made according to the scope of the patent application of the present invention shall fall within the scope covered by the present invention.

Claims

1. A water-based self-cleaning coating, characterized in that: In parts by weight, the components and amounts of the water-based self-cleaning coating are 560-650 parts of fluorine-modified polyacrylate emulsion, 275-357 parts of deionized water, 35-41 parts of film-forming aid, 5-10 parts of thickener, 1-2 parts of defoamer, 25-30 parts of reactive fluorocarbon leveling agent, 1-2 parts of anticorrosion and mildew inhibitor, and 0-3 parts of concentrated ammonia solution; The preparation steps of the reactive fluorocarbon leveling agent are as follows: a) mixing, by weight, 1000 parts of polyhexafluoropropylene oxide monomethanol, 440-460 parts of a 55 wt% aqueous solution of hydroiodic acid, 100-120 parts of phosphoric acid, and 80-100 parts of a phase transfer catalyst, tetrabutylammonium iodide, raising the temperature to 110-120° C., reacting for 4-7 hours, then cooling to 30-40° C., allowing the mixture to stand for separation and removing the aqueous layer. The organic layer was then washed three times with 1000 parts of deionized water, and the aqueous layer was removed to obtain a transparent solution; b) dissolving 16.8-23.6 parts of a fluorinated alcohol in 60-72 parts of tetrahydrofuran, adding 2.52-6.16 parts of a base, heating to 40-55° C., reacting for 6-10 hours, and then cooling to 35-40° C.; adding dropwise 15.2-18.3 parts of carbon disulfide over 0.5-1 hour, reacting at 35-40° C. for 2-5 hours, and then removing the tetrahydrofuran and excess carbon disulfide by distillation under reduced pressure; then adding 120-145 parts of tetrahydrofuran and 260-295 parts of the transparent solution obtained in step a), stirring at 45-55° C. for 16-24 hours, removing the tetrahydrofuran by distillation under reduced pressure, and recrystallizing from ethanol to obtain a fluorinated alkyl xanthate perfluoropolyether ester used as a chain transfer agent; c) adding 37.2-42.6 parts of fluorinated alkyl xanthate perfluoropolyether ester, 10-22 parts of acrylate soft monomer, 125-140 parts of solvent and 0.48-0.73 parts of oil-soluble initiator to a reactor, stirring uniformly, heating to 65-75° C. under nitrogen protection, reacting for 0.5 hour, and then dropwise adding a mixed monomer consisting of 30-47 parts of acrylate soft monomer, 42-60 parts of acrylate hard monomer, 10-14 parts of glycidyl methacrylate and 3-4 parts of hydrophilic monomer over 2-3 hours, continuing to react at this temperature for 4-6 hours, and then cooling to 30-40° C.; adjusting the pH to 8-9 with aqueous ammonia, and then slowly adding 12-16.8 parts of isophorone diamine, stirring and heating to 55-65° C., reacting for 4-7 hours, cooling to 20-30° C., adding 20-25 parts of deionized water, and stirring and dissolving uniformly to obtain the reactive fluorocarbon leveling agent.

2. The water-based self-cleaning coating according to claim 1, characterized in that: The preparation steps of the fluorine-modified polyacrylate emulsion are as follows: 1) Dissolve 5-8 parts of reactive anionic emulsifier in 180-210 parts of deionized water, and dropwise add a mixture of 130-160 parts of acrylic acid ester soft monomer, 135-175 parts of acrylic acid ester hard monomer, and 2-3 parts of hydrophilic monomer. Stir at 600-800 rpm for 0.5-1 hour to obtain pre-emulsion A. 2) Dissolve 7-10 parts of a reactive anionic emulsifier and 3-6 parts of a reactive nonionic emulsifier in 100-130 parts of deionized water, add dropwise a mixed monomer consisting of 85-105 parts of perfluoropolyether acrylate, 30-50 parts of acrylate soft monomer, 45-60 parts of acrylate hard monomer, 12-19 parts of a functional monomer, and 2-4 parts of itaconic acid, and stir at 600-800 rpm for 0.5-1 hour to obtain a pre-emulsion B; 3) Take 150-250 parts of deionized water, add 5-8 parts of reactive anionic emulsifier, 2-4 parts of reactive nonionic emulsifier and 1-2 parts of aqueous initiator, stir evenly and heat to 70-90°C, then add 10-15wt% of pre-emulsion A prepared in step 1), react for 0.3-0.5 hours, and then simultaneously dropwise add the remaining pre-emulsion A and 30 parts of an initiator aqueous solution containing 1-1.5 parts of aqueous initiator, and continue the addition for 2- 3 hours; after the addition of pre-emulsion A is completed, pre-emulsion B and 20 parts of an initiator aqueous solution containing 0.8-1.2 parts of an aqueous initiator are continued to be added dropwise at the same time, and the addition is continued for 1-2 hours. After the addition is completed, the temperature is continued to be kept for 2-3 hours, and then the temperature is lowered to 20-30° C., and the pH is adjusted to 7-9 with concentrated ammonia water. Then, 3-5 parts of a stabilizer and 6-10 parts of a hydrazide compound are added, and the gel is removed by filtering with a 500-mesh filter to obtain the fluorine-modified polyacrylate emulsion.

3. The water-based self-cleaning coating according to claim 2, characterized in that: The reactive anionic emulsifier is allyl polyoxyethylene ether ammonium sulfate; the reactive nonionic emulsifier is one of allyl polyethylene glycol ether APEG-500, APEG-700, and APEG800; the acrylic perfluoropolyether ester is perfluoropolyether methacrylate or perfluoropolyether acrylate; the functional monomer is acetoacetoxyethyl methacrylate; the aqueous initiator is one of potassium persulfate, ammonium persulfate, and sodium persulfate; the stabilizer is BY-9550; and the hydrazide compound is one of adipic acid dihydrazide, succinic acid dihydrazide, and glutaric acid dihydrazide.

4. The water-based self-cleaning coating according to claim 1, characterized in that: The structural formula of the polyhexafluoropropylene oxide monomethanol is [CF(CF3)CF2O] m CH2OH has an average molecular weight of 1000 Da; the fluorine-containing alcohol is one of perfluorotert-butyl alcohol, hexafluoroisopropanol, and 2,2,3,3,4,4,4-heptafluoro-1-butanol; the base is one of potassium hydroxide, sodium hydroxide, and lithium hydroxide; the solvent is propylene glycol dimethyl ether or dipropylene glycol dimethyl ether; and the oil-soluble initiator is azobisisobutyronitrile or azobisisoheptanenitrile.

5. The water-based self-cleaning coating according to claim 1 or 2, characterized in that: The soft acrylate monomer is one or more of butyl acrylate, butyl methacrylate, isooctyl acrylate, and lauryl acrylate; the hard acrylate monomer is one or more of methyl acrylate, methyl methacrylate, isobornyl acrylate, and isobornyl methacrylate; and the hydrophilic monomer is one of acrylic acid and methacrylic acid.

6. The water-based self-cleaning coating according to claim 1, wherein: The film-forming aid is one of Eastman Texanol, Dow Chemical Dowanol® DPnB, and Dow Chemical Dowanol® DPM; the thickener is one or more of Wanhua Chemical Vesmody® A406, Vesmody® A408, Vesmody® U601, and Vesmody® U902; the defoamer is one or more of Tego Foamex 825, Tego Foamex 810, and Tego Foamex 1488; and the preservative and mildew inhibitor is one of Dow Chemical Kathon® LXE and Rocima® 631.

7. The water-based self-cleaning coating according to claim 1, characterized in that: The water-based self-cleaning coating is prepared by mixing fluorine-modified polyacrylate emulsion, deionized water, film-forming aid, thickener, defoamer, reactive fluorocarbon leveling agent, antiseptic and mildew preventer and concentrated ammonia water in proportion, stirring at 600-800 rpm for 0.5-1 hour, and filtering with a 500-mesh filter to remove gel.

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