Preparation process of mildew-proof antibacterial self-cleaning coating

Abstract

The invention relates to a preparation process of a mildew-proof antibacterial self-cleaning coating. The preparation method comprises the following steps: preparation of a waterborne polyurethane emulsion, synthesis of waterborne polyurethane (WPU-TNO) of TNO, preparation of an antibacterial mildew-proof fatting agent through esterification reaction, preparation of dendritic mesoporous silica, modification of the dendritic mesoporous silica by APTES, preparation of a silica-loaded nano-silver antibacterial agent, and preparation of nano TiO2 self-cleaning hydrosol. According to preparation of the silicon dioxide loaded nano-silver / TiO2 self-cleaning / WPU-TNO antibacterial coating, an emulsification method and a lipidation method are creatively combined, the prepared material shows a good self-cleaning function and excellent antibacterial and mildew-proof performance, and the silicon dioxide loaded nano-silver / TiO2 self-cleaning / WPU-TNO antibacterial coating has the advantages of being stable, environmentally friendly, biosafe, excellent in self-cleaning function, mildew-proof, antibacterial and the like.

Description

Technical Field

[0001] The invention relates to a new material preparation, in particular to a preparation process of a mildew-proof, antibacterial and self-cleaning coating. Background Art

[0002] With the improvement of people's living standards and the enhancement of environmental awareness, the performance requirements for building materials and interior decoration materials are getting higher and higher. Especially in humid environments that are prone to bacteria, such as kitchens and bathrooms, the demand for mildew-proof and antibacterial coatings is increasing. In addition, with the development of the construction industry, higher requirements are also put forward for the weather resistance, stain resistance, self-cleaning and other properties of coatings.

[0003] Nanomaterials have unique physical and chemical properties. The application of nano-antibacterial agents such as nano-silver and nano-titanium dioxide in coatings can significantly improve the antibacterial properties and self-cleaning ability of coatings. By combining multiple antibacterial agents, antifouling agents, self-cleaning agents and other ingredients, a synergistic effect can be produced to improve the overall performance of coatings.

[0004] Traditional paints often have limited antibacterial effects and cannot effectively inhibit the growth and reproduction of bacteria and mold. Some paints are easily stained and difficult to clean during long-term use, affecting their appearance and service life. Paints that lack self-cleaning functions require manual cleaning after the surface is contaminated, which increases maintenance costs and time costs. Summary of the invention

[0005] In view of the above problems, the present invention provides a preparation process of a mildew-proof, antibacterial and self-cleaning coating.

[0006] The invention provides a preparation process of an anti-mildew and antibacterial self-cleaning coating, comprising the following steps: preparation of an aqueous polyurethane emulsion, synthesis of a waterborne polyurethane of TNO (WPU-TNO), preparation of an antibacterial and anti-mildew type fatliquor by esterification reaction, preparation of dendritic mesoporous silica, preparation of APTES-modified dendritic mesoporous silica, preparation of a silica-loaded nano-silver antibacterial agent, preparation of a nano-TiO2 self-cleaning hydrosol, and preparation of a silica-loaded nano-silver / TiO2 self-cleaning / WPU-TNO antibacterial coating.

[0007] Preferably, step (1) preparation of aqueous polyurethane emulsion Add polypropylene glycol and isophorone diisocyanate into a three-necked flask and stir to perform a prepolymerization reaction, then lower the system temperature, add acetone, then add a catalyst dibutyltin dilaurate, then mix dimethylolpropionic acid and 1,4-butanediol evenly and add them to the reaction system in four times, then titrate the isocyanate with dibutylamine, add TEA (triethylamine) to neutralize the emulsion; add deionized water, add EDA (ethylenediamine) after the emulsification is even, stir to obtain a WPU (waterborne polyurethane) emulsion; finally, evaporate the acetone by vacuum distillation to obtain an acetone-free waterborne polyurethane emulsion; Step (2) Synthesis of waterborne polyurethane of TNO (WPU-TNO) IPDI (isophorone diisocyanate), polyester polyol and DBTDL (isophorone diisocyanate) are added to a three-necked flask with mechanical stirring, and after the reaction, BDO (1,4-butanediol) and DMPA (2,2-bis(hydroxymethyl)propionic acid) are added, and TNO (hexahydro-1,3,5-tris(hydroxyethyl)-s-triazine) is used for chain extension, and DMF (N,N-dimethylformamide) is added to reduce the viscosity after the temperature is maintained for reaction, and TEA is added for neutralization after the temperature is lowered, and deionized water is added, and after dispersion, a deionized water solution of mixed EDA (anhydrous ethylenediamine) is added, and the water-based polyurethane emulsion of step (1) is added and evenly distributed on a polytetrafluoroethylene plate by casting, and a film is formed and dried at room temperature, and then a water-based polyurethane (WPU-TNO) of TNO is obtained by drying, and DMF and water are completely removed to obtain a coating film with uniform thickness, which is placed in a dryer for standby use; Step (3) Preparation of antibacterial and antifungal fatliquor by esterification reaction Add the waterborne polyurethane (WPU-TNO) of TNO prepared in step (2) and maleic anhydride, place the esterified oil in a water bath, slowly add a sodium metabisulfite aqueous solution dropwise with a separatory funnel, cool after the reaction, and adjust the pH value of the fatliquor to a certain value with ammonia water to obtain an antibacterial and antifungal fatliquor; Step (4) Preparation of dendritic mesoporous silica CTAB (hexadecyltrimethylammonium bromide) was dissolved in deionized water, and then ether, ethanol and ammonia water were added. After magnetic stirring, TEOS (tetraethyl orthosilicate) and APTES (3-aminopropyltriethoxysilane) were added dropwise and stirred, and then hydrochloric acid solution was added to adjust the pH, stirred again, and then the obtained solution was centrifuged, washed with ethanol and deionized water respectively, and finally dried to obtain dendritic mesoporous silica; Step (5) APTES modified dendritic mesoporous silica Disperse the dendritic mesoporous silica prepared in step (4) in toluene and perform ultrasonic treatment. Take a round-bottom flask, add the silica dispersion into the flask and then drop APTES into the flask. Centrifuge with magnetic stirring, separate, wash and dry to obtain modified dendritic mesoporous silica. Step (6) Preparation of silica-loaded nanosilver antibacterial agent Add silver nitrate solution and sodium borohydride solution, take the dendritic mesoporous silica modified in step (5), disperse it in ethanol and perform ultrasonic treatment; take the silver nitrate solution and add it to the ethanol solution, after the light shielding reaction, disperse PVP-K30 (polyvinyl pyrrolidone K30) in deionized water, and then add it dropwise to the reaction solution and stir; then take the sodium borohydride solution and add it dropwise to the reaction solution; immediately centrifuge after the addition, and wash with ethanol and deionized water; finally freeze-dry to obtain a silica-loaded nanosilver antibacterial agent; Step (7) Preparation of Nano-TiO2 Self-cleaning Hydrosol Dissolving butyl titanate in anhydrous ethanol to form a mixed solution of butyl titanate and ethanol; adding hydrochloric acid to distilled water to obtain a hydrochloric acid aqueous solution; then dripping the hydrochloric acid aqueous solution into the mixed solution of butyl titanate and ethanol under stirring; continuing to stir after the dripping is completed to obtain a milky white aqueous dispersion; finally sealing and letting it stand for aging to form a slightly yellowish translucent nano-TiO2 hydrosol; Step (8) Preparation of silica-loaded nanosilver / TiO2 self-cleaning / WPU-TNO antibacterial coating The silica-loaded nano-silver antibacterial agent prepared in step (6) and the nano-TiO2 self-cleaning hydrosol prepared in step (7) are ultrasonically dispersed in deionized water, and then the antibacterial and mildew-proof fatliquor prepared in step (3) is added, and the polyurethane dispersion is slowly dripped into the reaction system, and then deionized water is added, stirred until the mixture is uniform, and then emulsified, and acetone is removed by vacuum distillation; thus, the silica-loaded nano-silver / TiO2 self-cleaning / WPU-TNO antibacterial coating is obtained.

[0008] Preferably, step (1) preparation of aqueous polyurethane emulsion Add polypropylene glycol and isophorone diisocyanate into a three-necked flask and stir, and perform prepolymerization at 80-85°C for 90-100 minutes; then lower the system temperature to 80-85°C, add acetone, and then add 6-7 drops of catalyst dibutyltin dilaurate, and then mix dimethylolpropionic acid and 1,4-butanediol evenly and add them to the reaction system four times (once every 10-15 minutes), react for 95-100 minutes after adding, and then titrate the isocyanate with dibutylamine, and add TEA (triethylamine) to neutralize the emulsion; add deionized water, stir and emulsify, add EDA (ethylenediamine) after the emulsification is uniform, and stir to obtain WPU (waterborne polyurethane) emulsion; finally, evaporate the acetone by vacuum distillation to obtain an acetone-free waterborne polyurethane emulsion.

[0009] The invention has the advantages that TEA (triethylamine) neutralizes the emulsion, which can ensure the stability of the emulsion, and the polyurethane molecules are evenly dispersed in water to form a stable aqueous emulsion, and further improve the crosslinking degree and performance of the emulsion; Waterborne polyurethane emulsion has excellent film-forming, water resistance and weather resistance. At the same time, due to the precise control of reaction conditions and the full reaction of raw materials, the molecular weight distribution of the product is narrower and the performance is more stable.

[0010] Preferably, step (2) the synthesis of waterborne polyurethane of TNO (WPU-TNO) Add IPDI (isophorone diisocyanate), polyester polyol and DBTDL (isophorone diisocyanate) into a three-necked flask with mechanical stirring, react for 1-5 hours, then add BDO and DMPA and use TNO for chain extension, keep the temperature for reaction for 1-4 hours, then add DMF to reduce the viscosity, cool to 40-45°C, add TEA for neutralization for 30-35 minutes, add deionized water at a speed of 2500-3000 r / min, add deionized water solution mixed with EDA after dispersion, continue to disperse for 10-15 minutes, add the waterborne polyurethane emulsion of step (1), evenly distribute it on a polytetrafluoroethylene plate by casting, dry it at room temperature for 40-48 hours, and then dry it at 70-75°C for 36-45 hours to obtain a waterborne polyurethane of TNO (WPU-TNO), completely remove DMF and water to obtain a coating film with uniform thickness, and put it into a dryer for use.

[0011] The invention has the advantage that a water-based system is used in the synthesis process, which reduces the use of organic solvents (such as DMF) compared with traditional solvent-based polyurethanes, thereby reducing the emission of volatile organic compounds (VOCs), is more environmentally friendly, and meets the requirements of modern green chemistry and sustainable development; The introduction of TNO for chain extension can significantly improve the water resistance and solvent resistance of waterborne polyurethane. Through the dual curing process of casting film, room temperature drying and high temperature drying, a coating film with uniform thickness, smooth surface and no defects can be prepared; this high-quality coating film not only has excellent physical properties and chemical stability, but also has good adhesion and weather resistance, and can maintain its performance for a long time.

[0012] Preferably, step (3) is to prepare an antibacterial and antifungal fatliquor by esterification reaction. The molar ratio of oil to alcohol is 1-2:2-4, and the molar ratio of the waterborne polyurethane (WPU-TNO) of TNO prepared in step (2) to maleic anhydride is 1-5:0.7-0.9. The esterified oil is placed in a water bath at 70-75°C, and an aqueous sodium metabisulfite solution is slowly added dropwise using a separatory funnel. After the reaction, the temperature is lowered to 40-45°C, and the pH value of the fatliquor is adjusted to about 1-7 with ammonia water to obtain an antibacterial and anti-mildew type fatliquor.

[0013] The invention has the advantage that the fatliquor not only maintains the good permeability and moisturizing property of the traditional fatliquor to the material, but also helps to improve the ability to resist the growth of bacteria and mold, thereby extending the service life and shelf life of the product.

[0014] Preferably, step (4) preparation of dendritic mesoporous silica Dissolve 0.5-0.9 g of CTAB in 70-75 mL of deionized water, add 15-20 mL of ether, 5-15 mL of ethanol and ammonia water, stir magnetically for 25-30 min, add 2.5-5.5 mL of TEOS and APTES dropwise and stir for 1-4 h, then add hydrochloric acid solution to adjust the pH value of the solution to 1-7, stir again for 15-30 min, then centrifuge the resulting solution, wash with ethanol and deionized water 1-3 times, respectively, and finally dry at 55-60° C. for 1-6 h to obtain dendritic mesoporous silica.

[0015] The invention has the advantages that the mesoporous silica with a dendritic structure has a large specific surface area and pore volume, as well as good permeability and adsorption performance. The prepared dendritic mesoporous silica has uniform pore size distribution, good thermal stability and excellent adsorption performance.

[0016] Preferably, in step (5), APTES is used to modify the dendritic mesoporous silica. Take 450-500 mg of the dendritic mesoporous silica prepared in step (4) and disperse it in 50-55 mL of toluene and ultrasonicate for 1-2 hours; take a round-bottom flask, add the silica dispersion into the flask and then drop 2-5 mL of APTES, reflux at 85-95° C., stir magnetically for 15-30 minutes, centrifuge, separate, wash and dry to obtain modified dendritic mesoporous silica.

[0017] The advantage of adopting the present invention is that the amino group of APTES not only increases the hydrophilicity and biocompatibility of the material, but also provides an active site for subsequent functional modification, forms a stable chemical bond connection, and enhances the structural stability of the modified material; this stability enables the modified dendritic mesoporous silica to maintain its excellent performance in harsh environments.

[0018] Preferably, step (6) preparation of silica-loaded nanosilver antibacterial agent Prepare 0.002-0.006mol·L -1 Silver nitrate solution, 0.005-0.009mol·L -1 The sodium borohydride solution is set aside; 35-40 mg of the dendritic mesoporous silica modified in step (5) is dispersed in 20-25 mL of ethanol and ultrasonicated for 85-90 min; 20-25 mL of silver nitrate solution is added to the ethanol solution, and after shading for 2-10 h, 1-4 mg of PVP-K30 is dispersed in 10-15 mL of deionized water, and then added dropwise to the reaction solution, and stirred for 15-30 min; then 5-10 mL of sodium borohydride solution is added dropwise to the reaction solution; centrifugation is immediately performed after the addition is completed, and the solution is washed with ethanol and deionized water for 1-3 times each; and finally, freeze-dried for 10-15 h to obtain a silica-loaded nanosilver antibacterial agent.

[0019] The invention has the advantages that the nano silver particles can more effectively contact with bacteria and destroy their cell structure due to their small size effect and surface effect, thereby achieving a rapid sterilization effect, and the prepared antibacterial agent has excellent antibacterial performance; The modified dendritic mesoporous silica is used as a carrier, and its unique structure and surface properties enable the nanosilver particles to be evenly dispersed and stably attached to its surface; this good dispersibility and stability not only improves the antibacterial efficiency of the antibacterial agent, but also extends its service life.

[0020] The third technical objective of the present invention is achieved through the following technical solutions: Preferably, step (7) preparation of nano-TiO2 self-cleaning hydrosol Dissolve butyl titanate in anhydrous ethanol to form a mixed solution of butyl titanate and ethanol; at the same time, add 35-40% hydrochloric acid into distilled water to obtain a hydrochloric acid aqueous solution with a pH of 1.5-2.5; then drip the butyl titanate and ethanol mixed solution into the hydrochloric acid aqueous solution at a rate of 1.0-2.0 drops / s under stirring conditions; after the dropwise addition is completed, continue stirring for 1-5 hours to obtain a milky white aqueous dispersion; finally, seal it and let it stand for aging to form a slightly yellowish translucent nano-TiO2 hydrosol.

[0021] The advantage of the present invention is that the prepared nano-TiO2 hydrosol has high purity and good stability, and this stability makes the hydrosol less likely to agglomerate or precipitate during storage and use, thereby ensuring its long-term effectiveness. Nano-TiO2 has excellent photocatalytic properties and can decompose organic matter and kill bacteria under ultraviolet light, thereby achieving a self-cleaning effect and significantly reducing cleaning costs.

[0022] Preferably, step (8) preparation of silica-loaded nanosilver / TiO2 self-cleaning / WPU-TNO antibacterial coating The silica-loaded nano-silver antibacterial agent prepared in step (6) and the nano-TiO2 self-cleaning hydrosol prepared in step (7) are ultrasonically dispersed in deionized water, and then the antibacterial and mildew-proof fatliquor prepared in step (3) is added, and the polyurethane dispersion is slowly dripped into the reaction system, and then deionized water is added, stirred until the mixture is uniform, and then emulsified, and acetone is removed by vacuum distillation; thus, the silica-loaded nano-silver / TiO2 self-cleaning / WPU-TNO antibacterial coating is obtained.

[0023] The advantage of adopting the present invention is that the prepared material has multiple antibacterial and self-cleaning functions, combining the antibacterial properties of silica-loaded nanosilver and the self-cleaning properties of nano-TiO2 to form a dual protection mechanism. The coating can better penetrate into the interior of the substrate and form a dense coating, thereby improving the adhesion and durability of the coating.

[0024] In summary, the present invention has the following beneficial effects: 1. The present invention has the advantages that TEA (triethylamine) neutralizes the emulsion, which can ensure the stability of the emulsion, and the polyurethane molecules are evenly dispersed in water to form a stable aqueous emulsion, and further improve the crosslinking degree and performance of the emulsion; 2. The present invention has the advantages that the aqueous polyurethane emulsion has excellent film-forming properties, water resistance, and weather resistance. At the same time, due to the precise control of the reaction conditions and the full reaction of the raw materials, the molecular weight distribution of the product is narrower and the performance is more stable; 3. The present invention has the advantage that a water-based system is used in the synthesis process, which reduces the use of organic solvents (such as DMF) compared to traditional solvent-based polyurethanes, thereby reducing the emission of volatile organic compounds (VOCs), is more environmentally friendly, and meets the requirements of modern green chemistry and sustainable development; 4. The present invention has the advantages that the introduction of TNO for chain extension can significantly improve the water resistance and solvent resistance of waterborne polyurethane, and a coating film with uniform thickness, smooth surface and no defects can be prepared through a dual curing process of film casting, room temperature drying and high temperature drying; such high-quality coating film not only has excellent physical properties and chemical stability, but also has good adhesion and weather resistance, and can maintain its performance unchanged for a long time; 5. The invention has the advantage that the fatliquor not only maintains the good permeability and moisturizing properties of the traditional fatliquor to the material, but also helps to improve the ability to resist the growth of bacteria and mold, thereby extending the service life and shelf life of the product; 6. The advantages of the present invention are that the mesoporous silica with a dendritic structure has a large specific surface area and pore volume, and also has good permeability and adsorption performance. The prepared dendritic mesoporous silica has a uniform pore size distribution, good thermal stability and excellent adsorption performance; 7. The advantage of the present invention is that the amino group of APTES not only increases the hydrophilicity and biocompatibility of the material, but also provides active sites for subsequent functional modification, forms stable chemical bond connections, and enhances the structural stability of the modified material; this stability enables the modified dendritic mesoporous silica to maintain its excellent performance in harsh environments; 8. The advantages of the present invention are that the nano silver particles can more effectively contact with bacteria and destroy their cell structures due to their small size effect and surface effect, thereby achieving a rapid sterilization effect, and the prepared antibacterial agent has excellent antibacterial properties; the modified dendritic mesoporous silica is used as a carrier, and its unique structure and surface properties enable the nano silver particles to be uniformly dispersed and stably attached to its surface; such good dispersibility and stability not only improve the antibacterial efficiency of the antibacterial agent, but also extend its service life; 9. The advantages of the present invention are that the prepared nano-TiO2 hydrosol has high purity and good stability, which makes it difficult for the hydrosol to agglomerate or precipitate during storage and use, thereby ensuring its long-term effectiveness; nano-TiO2 has excellent photocatalytic properties, and can decompose organic matter and kill bacteria under ultraviolet light, thereby achieving a self-cleaning effect and significantly reducing cleaning costs; 10. The advantage of the present invention is that the prepared material has multiple antibacterial and self-cleaning functions, combining the antibacterial properties of silica-loaded nanosilver and the self-cleaning properties of nano-TiO2 to form a dual protection mechanism. The coating can better penetrate into the interior of the substrate and form a dense coating, thereby improving the adhesion and durability of the coating. BRIEF DESCRIPTION OF THE DRAWINGS

[0025] Figure 1 The invention discloses a preparation process of a mildew-proof, antibacterial and self-cleaning coating. DETAILED DESCRIPTION

[0026] The following examples are used to illustrate the present invention, but are not intended to limit the scope of the present invention. Without departing from the spirit and substance of the present invention, modifications or substitutions made to the methods, steps or conditions of the present invention are within the scope of the present invention.

[0027] If not specifically stated, the technical means used in the examples are conventional means known to those skilled in the art. In addition, all the raw materials used in the examples are known commercial products. Example 1

[0028] Step (1) Preparation of waterborne polyurethane emulsion Add polypropylene glycol and isophorone diisocyanate into a three-necked flask and stir, and perform prepolymerization at 80°C for 90 minutes; then lower the system temperature to 80°C, add acetone, and then add 6 drops of catalyst dibutyltin dilaurate, and then mix dimethylolpropionic acid and 1,4-butanediol evenly and add them to the reaction system four times (once every 10 minutes), react for 95 minutes after the addition, and then titrate the isocyanate with dibutylamine, and add TEA (triethylamine) to neutralize the emulsion; add deionized water, stir and emulsify, and add EDA (ethylenediamine) after the emulsification is uniform, and stir to obtain WPU (waterborne polyurethane) emulsion; finally, evaporate the acetone by vacuum distillation to obtain an acetone-free waterborne polyurethane emulsion; Step (2) Synthesis of waterborne polyurethane of TNO (WPU-TNO) Add IPDI (isophorone diisocyanate), polyester polyol and DBTDL (isophorone diisocyanate) into a three-necked flask with mechanical stirring, react for 5 hours, add BDO and DMPA, and use TNO for chain extension, keep the temperature for reaction for 1 hour, add DMF to reduce viscosity, cool to 40°C, add TEA for neutralization for 30 minutes, add deionized water at a speed of 2500 r / min, add deionized water solution mixed with EDA after dispersion, continue to disperse for 10 minutes, add the waterborne polyurethane emulsion in step (1), evenly distribute it on a polytetrafluoroethylene plate by casting, dry it at room temperature for 40 hours, and then dry it at 70°C for 36 hours to obtain a waterborne polyurethane of TNO (WPU-TNO), completely remove DMF and water to obtain a coating film with uniform thickness, and put it into a dryer for use; Step (3) Preparation of antibacterial and antifungal fatliquor by esterification reaction The molar ratio of oil to alcohol is 1:2, and the molar ratio of the waterborne polyurethane (WPU-TNO) of TNO prepared in step (2) to maleic anhydride is 1:0.7. The esterified oil is placed in a 70°C water bath, and an aqueous sodium metabisulfite solution is slowly added dropwise using a separatory funnel. After the reaction, the temperature is lowered to 40°C, and the pH value of the fatliquor is adjusted to about 2 with aqueous ammonia to obtain an antibacterial and antifungal fatliquor. Step (4) Preparation of dendritic mesoporous silica 0.5 g of CTAB was dissolved in 70 mL of deionized water, and then 15 mL of ether, 10 mL of ethanol and ammonia water were added. After magnetic stirring for 25 min, 2.5 mL of TEOS and APTES were added dropwise and stirred for 2 h. Then, hydrochloric acid solution was added to adjust the pH value of the solution to 2. The solution was stirred for another 18 min and then centrifuged. The solution was washed twice with ethanol and deionized water respectively, and finally dried at 56 ° C for 5 h to obtain dendritic mesoporous silica. Step (5) APTES modified dendritic mesoporous silica 460 mg of the dendritic mesoporous silica prepared in step (4) was dispersed in 51 mL of toluene and ultrasonicated for 1 h; a round-bottom flask was taken, the silica dispersion was added to the flask, and then 2 mL of APTES was added dropwise, refluxed at 85° C., magnetically stirred for 15 min, centrifuged, separated, washed, and dried to obtain modified dendritic mesoporous silica; Step (6) Preparation of silica-loaded nanosilver antibacterial agent Prepare 0.002 mol·L -1 Silver nitrate solution, 0.005 mol·L -1 35 mg of the modified dendritic mesoporous silica in step (5) was dispersed in 20 mL of ethanol and subjected to ultrasonic treatment for 85 min; 20 mL of silver nitrate solution was added to the ethanol solution, and after shading for 2 h, 1 mg of PVP-K30 was dispersed in 10 mL of deionized water, and then added dropwise to the reaction solution, and stirred for 15 min; then 5 mL of sodium borohydride solution was added dropwise to the reaction solution; centrifuged immediately after the addition, and washed once with ethanol and deionized water; finally, freeze-dried for 10 h to obtain a silica-loaded nanosilver antibacterial agent; Step (7) Preparation of Nano-TiO2 Self-cleaning Hydrosol Dissolve butyl titanate in anhydrous ethanol to form a mixed solution of butyl titanate and ethanol; add 35% hydrochloric acid to distilled water to obtain a hydrochloric acid aqueous solution with a pH of 1.5; then drip the butyl titanate and ethanol mixed solution into the hydrochloric acid aqueous solution at a rate of 1.0 drop / s under stirring; continue stirring for 2 hours after the dropwise addition to obtain a milky white aqueous dispersion; finally seal the solution and allow it to stand for aging to form a slightly yellowish translucent nano-TiO2 hydrosol; Step (8) Preparation of silica-loaded nanosilver / TiO2 self-cleaning / WPU-TNO antibacterial coating The silica-loaded nano-silver antibacterial agent prepared in step (6) and the nano-TiO2 self-cleaning hydrosol prepared in step (7) are ultrasonically dispersed in deionized water, and then the antibacterial and mildew-proof fatliquor prepared in step (3) is added, and the polyurethane dispersion is slowly dripped into the reaction system, and then deionized water is added, stirred until the mixture is uniform, and then emulsified, and acetone is removed by vacuum distillation; thus, the silica-loaded nano-silver / TiO2 self-cleaning / WPU-TNO antibacterial coating is obtained. Example 2

[0029] Step (1) Preparation of waterborne polyurethane emulsion Add polypropylene glycol and isophorone diisocyanate into a three-necked flask and stir, and perform prepolymerization at 82°C for 95 minutes; then lower the system temperature to 82°C, add acetone, and then add 6 drops of catalyst dibutyltin dilaurate, and then mix dimethylolpropionic acid and 1,4-butanediol evenly and add them to the reaction system four times (once every 12 minutes), react for 96 minutes after the addition, and then titrate the isocyanate with dibutylamine, and add TEA (triethylamine) to neutralize the emulsion; add deionized water, stir and emulsify, and add EDA (ethylenediamine) after the emulsification is uniform, and stir to obtain WPU (waterborne polyurethane) emulsion; finally, evaporate the acetone by vacuum distillation to obtain an acetone-free waterborne polyurethane emulsion; Step (2) Synthesis of waterborne polyurethane of TNO (WPU-TNO) Add IPDI (isophorone diisocyanate), polyester polyol and DBTDL (isophorone diisocyanate) into a three-necked flask with mechanical stirring, react for 4 hours, add BDO and DMPA, and use TNO for chain extension, keep the temperature for reaction for 2 hours, add DMF to reduce viscosity, cool to 42°C, add TEA for neutralization for 32 minutes, add deionized water at a speed of 2600 r / min, add deionized water solution mixed with EDA after dispersion, continue to disperse for 12 minutes, add the waterborne polyurethane emulsion in step (1), evenly distribute it on a polytetrafluoroethylene plate by casting, dry it at room temperature for 42 hours, and then dry it at 72°C for 40 hours to obtain a waterborne polyurethane of TNO (WPU-TNO), completely remove DMF and water to obtain a coating film with uniform thickness, and put it into a dryer for use; Step (3) Preparation of antibacterial and antifungal fatliquor by esterification reaction The molar ratio of oil to alcohol is 1:2, and the molar ratio of the waterborne polyurethane (WPU-TNO) of TNO prepared in step (2) to maleic anhydride is 1:0.7. The esterified oil is placed in a water bath at 73°C, and an aqueous sodium metabisulfite solution is slowly added dropwise using a separatory funnel. After the reaction, the temperature is lowered to 43°C, and the pH value of the fatliquor is adjusted to about 5 with aqueous ammonia to obtain an antibacterial and antifungal fatliquor. Step (4) Preparation of dendritic mesoporous silica 0.8 g of CTAB was dissolved in 75 mL of deionized water, and then 16 mL of ether, 10 mL of ethanol and ammonia water were added. After magnetic stirring for 26 min, 3.5 mL of TEOS and APTES were added dropwise and stirred for 2 h. Then, hydrochloric acid solution was added to adjust the pH value of the solution to 2. The solution was stirred for another 25 min and then centrifuged. The solution was washed twice with ethanol and deionized water respectively, and finally dried at 58 ° C for 5 h to obtain dendritic mesoporous silica. Step (5) APTES modified dendritic mesoporous silica 460 mg of the dendritic mesoporous silica prepared in step (4) was dispersed in 52 mL of toluene and ultrasonicated for 2 h; a round-bottom flask was taken, the silica dispersion was added to the flask, and then 3 mL of APTES was added dropwise, refluxed at 86° C., magnetically stirred for 16 min, centrifuged, separated, washed, and dried to obtain modified dendritic mesoporous silica; Step (6) Preparation of silica-loaded nanosilver antibacterial agent Prepare 0.003 mol·L -1 Silver nitrate solution, 0.006 mol·L -1 36 mg of the modified dendritic mesoporous silica in step (5) was dispersed in 24 mL of ethanol and subjected to ultrasonic treatment for 86 min; 25 mL of silver nitrate solution was added to the ethanol solution, and after 5 h of light shielding, 2 mg of PVP-K30 was dispersed in 13 mL of deionized water, and then added dropwise to the reaction solution, and stirred for 25 min; then 8 mL of sodium borohydride solution was added dropwise to the reaction solution; centrifuged immediately after the addition, and washed twice with ethanol and deionized water; finally, freeze-dried for 12 h to obtain a silica-loaded nanosilver antibacterial agent; Step (7) Preparation of Nano-TiO2 Self-cleaning Hydrosol Dissolve butyl titanate in anhydrous ethanol to form a mixed solution of butyl titanate and ethanol; add 36% hydrochloric acid to distilled water to obtain a hydrochloric acid aqueous solution with a pH of 1.5; then drip the butyl titanate and ethanol mixed solution into the hydrochloric acid aqueous solution at a rate of 1.0 drop / s under stirring; continue stirring for 2 hours after the dropwise addition to obtain a milky white aqueous dispersion; finally seal the solution and allow it to stand for aging to form a slightly yellowish translucent nano-TiO2 hydrosol; Step (8) Preparation of silica-loaded nanosilver / TiO2 self-cleaning / WPU-TNO antibacterial coating The silica-loaded nano-silver antibacterial agent prepared in step (6) and the nano-TiO2 self-cleaning hydrosol prepared in step (7) are ultrasonically dispersed in deionized water, and then the antibacterial and mildew-proof fatliquor prepared in step (3) is added, and the polyurethane dispersion is slowly dripped into the reaction system, and then deionized water is added, stirred until the mixture is uniform, and then emulsified, and acetone is removed by vacuum distillation; thus, the silica-loaded nano-silver / TiO2 self-cleaning / WPU-TNO antibacterial coating is obtained. Example 3

[0030] Step (1) Preparation of waterborne polyurethane emulsion Add polypropylene glycol and isophorone diisocyanate into a three-necked flask and stir, and prepolymerize at 85°C for 100 minutes; then lower the system temperature to 85°C, add acetone, then add 7 drops of catalyst dibutyltin dilaurate, then mix dimethylolpropionic acid and 1,4-butanediol evenly and add them to the reaction system four times (once every 15 minutes), react for 100 minutes after adding, then titrate the isocyanate with dibutylamine, add TEA (triethylamine) to neutralize the emulsion; add deionized water, stir and emulsify, add EDA (ethylenediamine) and stir after the emulsification is uniform, and obtain WPU (waterborne polyurethane) emulsion; finally, evaporate the acetone by vacuum distillation to obtain an acetone-free waterborne polyurethane emulsion; Step (2) Synthesis of waterborne polyurethane of TNO (WPU-TNO) Add IPDI (isophorone diisocyanate), polyester polyol and DBTDL (isophorone diisocyanate) into a three-necked flask with mechanical stirring, react for 5 hours, add BDO and DMPA, and use TNO for chain extension, keep the temperature for reaction for 4 hours, add DMF to reduce viscosity, cool to 45°C, add TEA for neutralization for 35 minutes, add deionized water at a speed of 3000 r / min, add deionized water solution mixed with EDA after dispersion, continue to disperse for 15 minutes, add the waterborne polyurethane emulsion in step (1), evenly distribute it on a polytetrafluoroethylene plate by casting, dry it at room temperature for 48 hours, and then dry it at 75°C for 45 hours to obtain a waterborne polyurethane of TNO (WPU-TNO), completely remove DMF and water to obtain a coating film with uniform thickness, and put it into a dryer for use; Step (3) Preparation of antibacterial and antifungal fatliquor by esterification reaction The molar ratio of oil to alcohol is 2:4, and the molar ratio of the waterborne polyurethane (WPU-TNO) of TNO prepared in step (2) to maleic anhydride is 5:0.9. The esterified oil is placed in a water bath at 75°C, and an aqueous sodium metabisulfite solution is slowly added dropwise using a separatory funnel. After the reaction, the temperature is lowered to 45°C, and the pH value of the fatliquor is adjusted to about 7 with aqueous ammonia to obtain an antibacterial and antifungal fatliquor. Step (4) Preparation of dendritic mesoporous silica 0.9 g of CTAB was dissolved in 75 mL of deionized water, and then 20 mL of ether, 15 mL of ethanol and ammonia water were added. After magnetic stirring for 30 min, 5.5 mL of TEOS and APTES were added dropwise and stirred for 4 h. Then, hydrochloric acid solution was added to adjust the pH value of the solution to 7. The solution was stirred for another 30 min and then centrifuged. The solution was washed with ethanol and deionized water for 3 times, respectively, and finally dried at 60 ° C for 6 h to obtain dendritic mesoporous silica. Step (5) APTES modified dendritic mesoporous silica 500 mg of the dendritic mesoporous silica prepared in step (4) was dispersed in 55 mL of toluene and ultrasonicated for 2 h; a round-bottom flask was taken, the silica dispersion was added to the flask, and then 5 mL of APTES was added dropwise, refluxed at 95° C., magnetically stirred for 30 min, centrifuged, separated, washed, and dried to obtain modified dendritic mesoporous silica; Step (6) Preparation of silica-loaded nanosilver antibacterial agent Prepare 0.006 mol·L -1 Silver nitrate solution, 0.009 mol·L -1 40 mg of the modified dendritic mesoporous silica in step (5) was dispersed in 25 mL of ethanol and subjected to ultrasonic treatment for 90 min. 25 mL of silver nitrate solution was added to the ethanol solution. After shading for 10 h, 4 mg of PVP-K30 was dispersed in 15 mL of deionized water and then added dropwise to the reaction solution and stirred for 30 min. 10 mL of sodium borohydride solution was then added dropwise to the reaction solution. After the addition was completed, the solution was immediately centrifuged and washed with ethanol and deionized water for 3 times each. Finally, the solution was freeze-dried for 15 h to obtain a silica-loaded nanosilver antibacterial agent. Step (7) Preparation of Nano-TiO2 Self-cleaning Hydrosol Dissolve butyl titanate in anhydrous ethanol to form a mixed solution of butyl titanate and ethanol; add 40% hydrochloric acid to distilled water to obtain a hydrochloric acid aqueous solution with a pH of 2.5; then drip the butyl titanate and ethanol mixed solution into the hydrochloric acid aqueous solution at a rate of 2.0 drops / s under stirring; continue stirring for 5 hours after the dropwise addition to obtain a milky white aqueous dispersion; finally seal the solution and allow it to stand for aging to form a slightly yellowish translucent nano-TiO2 hydrosol; Step (8) Preparation of silica-loaded nanosilver / TiO2 self-cleaning / WPU-TNO antibacterial coating The silica-loaded nano-silver antibacterial agent prepared in step (6) and the nano-TiO2 self-cleaning hydrosol prepared in step (7) are ultrasonically dispersed in deionized water, and then the antibacterial and mildew-proof fatliquor prepared in step (3) is added, and the polyurethane dispersion is slowly dripped into the reaction system, and then deionized water is added, stirred until the mixture is uniform, and then emulsified, and acetone is removed by vacuum distillation; thus, the silica-loaded nano-silver / TiO2 self-cleaning / WPU-TNO antibacterial coating is obtained. Example 4

[0031] Step (1) Preparation of waterborne polyurethane emulsion Add polypropylene glycol and isophorone diisocyanate into a three-necked flask and stir, and prepolymerize at 85°C for 100 minutes; then lower the system temperature to 80°C, add acetone, and then add 6 drops of catalyst dibutyltin dilaurate, and then mix dimethylolpropionic acid and 1,4-butanediol evenly and add them to the reaction system four times (once every 15 minutes), react for 100 minutes after adding, and then titrate the isocyanate with dibutylamine, and add TEA (triethylamine) to neutralize the emulsion; add deionized water, stir and emulsify, and add EDA (ethylenediamine) after the emulsification is uniform and stir to obtain WPU (waterborne polyurethane) emulsion; finally, evaporate the acetone by vacuum distillation to obtain an acetone-free waterborne polyurethane emulsion; Step (2) Synthesis of waterborne polyurethane of TNO (WPU-TNO) Add IPDI (isophorone diisocyanate), polyester polyol and DBTDL (isophorone diisocyanate) into a three-necked flask with mechanical stirring, react for 2 hours, add BDO and DMPA, and use TNO for chain extension, keep the temperature for reaction for 4 hours, add DMF to reduce viscosity, cool to 40°C, add TEA for neutralization for 30 minutes, add deionized water at a speed of 3000 r / min, add deionized water solution mixed with EDA after dispersion, continue to disperse for 15 minutes, add the waterborne polyurethane emulsion in step (1), evenly distribute it on a polytetrafluoroethylene plate by casting, dry it at room temperature for 48 hours, and then dry it at 75°C for 36 hours to obtain a waterborne polyurethane of TNO (WPU-TNO), completely remove DMF and water to obtain a coating with uniform thickness, and put it into a dryer for use; Step (3) Preparation of antibacterial and antifungal fatliquor by esterification reaction The molar ratio of oil to alcohol is 1:2, and the molar ratio of the waterborne polyurethane (WPU-TNO) of TNO prepared in step (2) to maleic anhydride is 1:0.7. The esterified oil is placed in a water bath at 75°C, and an aqueous sodium metabisulfite solution is slowly added dropwise using a separatory funnel. After the reaction, the temperature is lowered to 45°C, and the pH value of the fatliquor is adjusted to about 7 with ammonia water to obtain an antibacterial and antifungal fatliquor. Step (4) Preparation of dendritic mesoporous silica 0.5 g of CTAB was dissolved in 70 mL of deionized water, and then 20 mL of ether, 10 mL of ethanol and ammonia water were added. After magnetic stirring for 30 min, 2.5 mL of TEOS and APTES were added dropwise and stirred for 4 h. Then, hydrochloric acid solution was added to adjust the pH value of the solution to 7. The solution was stirred for 15 min again and then centrifuged. The solution was washed with ethanol and deionized water for 3 times respectively, and finally dried at 60 ° C for 6 h to obtain dendritic mesoporous silica. Step (5) APTES modified dendritic mesoporous silica 500 mg of the dendritic mesoporous silica prepared in step (4) was dispersed in 50 mL of toluene and ultrasonicated for 1 h; a round-bottom flask was taken, the silica dispersion was added to the flask, and then 2 mL of APTES was added dropwise, refluxed at 85° C., magnetically stirred for 15 min, centrifuged, separated, washed, and dried to obtain modified dendritic mesoporous silica; Step (6) Preparation of silica-loaded nanosilver antibacterial agent Prepare 0.002 mol·L -1 Silver nitrate solution, 0.005 mol·L -1 of sodium borohydride solution for later use; take 40 mg of the dendritic mesoporous silica modified in step (5) and disperse it in 20 mL of ethanol, and ultrasonicate for 90 min; take 20 mL of silver nitrate solution and add it to the ethanol solution, shade the reaction for 2 h, then disperse 4 mg of PVP-K30 in 10 mL of deionized water, and then add it dropwise to the reaction solution, and stir for 30 min; then take 10 mL of sodium borohydride solution and add it dropwise to the reaction solution; immediately centrifuge after the addition, and wash with ethanol and deionized water 3 times each; finally freeze-dry for 15 h to obtain a silica-loaded nanosilver antibacterial agent; Step (7) Preparation of Nano-TiO2 Self-cleaning Hydrosol Dissolve butyl titanate in anhydrous ethanol to form a mixed solution of butyl titanate and ethanol; add 37% hydrochloric acid to distilled water to obtain a hydrochloric acid aqueous solution with a pH of 1.5; then drip the butyl titanate and ethanol mixed solution into the hydrochloric acid aqueous solution at a rate of 1.0 drop / s under stirring; continue stirring for 1 hour after the dropwise addition to obtain a milky white aqueous dispersion; finally seal the solution and allow it to stand for aging to form a slightly yellowish translucent nano-TiO2 hydrosol; Step (8) Preparation of silica-loaded nanosilver / TiO2 self-cleaning / WPU-TNO antibacterial coating The silica-loaded nano-silver antibacterial agent prepared in step (6) and the nano-TiO2 self-cleaning hydrosol prepared in step (7) are ultrasonically dispersed in deionized water, and then the antibacterial and mildew-proof fatliquor prepared in step (3) is added, and the polyurethane dispersion is slowly dripped into the reaction system, and then deionized water is added, stirred until the mixture is uniform, and then emulsified, and acetone is removed by vacuum distillation; thus, the silica-loaded nano-silver / TiO2 self-cleaning / WPU-TNO antibacterial coating is obtained. Comparative Example 1

[0032] Step (1) Preparation of waterborne polyurethane emulsion Add polypropylene glycol and isophorone diisocyanate into a three-necked flask and stir, and perform prepolymerization at 90°C for 150 minutes; then lower the system temperature to 90°C, add acetone, and then add 10 drops of catalyst dibutyltin dilaurate, and then mix dimethylolpropionic acid and 1,4-butanediol evenly and add them to the reaction system four times (once every 30 minutes), react for 100 minutes after the addition, and then titrate the isocyanate with dibutylamine, and add TEA (triethylamine) to neutralize the emulsion; add deionized water, stir and emulsify, and add EDA (ethylenediamine) after the emulsification is uniform and stir to obtain WPU (waterborne polyurethane) emulsion; finally, evaporate the acetone by vacuum distillation to obtain an acetone-free waterborne polyurethane emulsion; Step (2) Synthesis of waterborne polyurethane of TNO (WPU-TNO) Add IPDI (isophorone diisocyanate), polyester polyol and DBTDL (isophorone diisocyanate) into a three-necked flask with mechanical stirring, react for 10 hours, add BDO and DMPA, and use TNO for chain extension, keep the temperature for reaction for 10 hours, add DMF to reduce viscosity, cool to 60°C, add TEA for neutralization for 60 minutes, add deionized water at a speed of 3000 r / min, add deionized water solution mixed with EDA after dispersion, continue to disperse for 15 minutes, add the waterborne polyurethane emulsion in step (1), evenly distribute it on a polytetrafluoroethylene plate by casting, dry it at room temperature for 60 hours, and then dry it at 80°C for 60 hours to obtain a waterborne polyurethane of TNO (WPU-TNO), completely remove DMF and water to obtain a coating film with uniform thickness, and put it into a dryer for use; Step (3) Preparation of antibacterial and antifungal fatliquor by esterification reaction The molar ratio of oil to alcohol is 1:2, and the molar ratio of the waterborne polyurethane (WPU-TNO) of TNO prepared in step (2) to maleic anhydride is 1:0.7. The esterified oil is placed in a water bath at 80°C, and an aqueous sodium metabisulfite solution is slowly added dropwise using a separatory funnel. After the reaction, the temperature is lowered to 60°C, and the pH value of the fatliquor is adjusted to about 6 with aqueous ammonia to obtain an antibacterial and antifungal fatliquor. Step (4) Preparation of dendritic mesoporous silica 0.6 g of CTAB was dissolved in 80 mL of deionized water, and then 25 mL of ether, 25 mL of ethanol and ammonia water were added. After magnetic stirring for 60 min, 6.5 mL of TEOS and APTES were added dropwise and stirred for 6 h. Then, hydrochloric acid solution was added to adjust the pH value of the solution to 10. The solution was stirred for 35 min again and then centrifuged. The solution was washed with ethanol and deionized water for 5 times, respectively, and finally dried at 65 ° C for 7 h to obtain dendritic mesoporous silica. Step (5) APTES modified dendritic mesoporous silica 550 mg of the dendritic mesoporous silica prepared in step (4) was dispersed in 60 mL of toluene and ultrasonicated for 3 h; a round-bottom flask was taken, the silica dispersion was added to the flask, and then 6 mL of APTES was added dropwise, refluxed at 100° C., magnetically stirred for 35 min, centrifuged, separated, washed, and dried to obtain modified dendritic mesoporous silica; Step (6) Preparation of silica-loaded nanosilver antibacterial agent Prepare 0.003 mol·L -1 Silver nitrate solution, 0.008 mol·L -1 of sodium borohydride solution for later use; 45 mg of the dendritic mesoporous silica modified in step (5) was dispersed in 35 mL of ethanol and ultrasonicated for 100 min; 30 mL of silver nitrate solution was added to the ethanol solution, and after 6 h of light shielding, 5 mg of PVP-K30 was dispersed in 30 mL of deionized water, and then added dropwise to the reaction solution, and stirred for 35 min; then 15 mL of sodium borohydride solution was added dropwise to the reaction solution; centrifuged immediately after the addition, and washed twice with ethanol and deionized water respectively; finally, freeze-dried for 25 h to obtain a silica-loaded nanosilver antibacterial agent; Step (7) Preparation of silica-loaded nanosilver / TiO2 self-cleaning / WPU-TNO antibacterial coating The silica-loaded nanosilver antibacterial agent prepared in step (6) is ultrasonically dispersed in deionized water, and then the antibacterial and mildew-proof fatliquor prepared in step (3) is added, and the polyurethane dispersion is slowly dripped into the reaction system, and then deionized water is added, stirred until the mixture is uniform, and then emulsified, and acetone is removed by vacuum distillation; thus, the silica-loaded nanosilver / TiO2 self-cleaning / WPU-TNO antibacterial coating is obtained. Comparative Example 2

[0033] Step (1) Preparation of waterborne polyurethane emulsion Add polypropylene glycol and isophorone diisocyanate into a three-necked flask and stir, and prepolymerize at 75°C for 85 minutes; then lower the system temperature to 65°C, add acetone, and then add 2 drops of catalyst dibutyltin dilaurate, and then mix dimethylolpropionic acid and 1,4-butanediol evenly and add them to the reaction system four times (once every 5 minutes), react for 90 minutes after the addition, and then titrate the isocyanate with dibutylamine, and add TEA (triethylamine) to neutralize the emulsion; add deionized water, stir and emulsify, and add EDA (ethylenediamine) after the emulsification is uniform, and stir to obtain WPU (waterborne polyurethane) emulsion; finally, evaporate the acetone by vacuum distillation to obtain an acetone-free waterborne polyurethane emulsion; Step (2) Synthesis of waterborne polyurethane of TNO (WPU-TNO) Add IPDI (isophorone diisocyanate), polyester polyol and DBTDL (isophorone diisocyanate) into a three-necked flask with mechanical stirring, react for 2 hours, add BDO and DMPA, and use TNO for chain extension, keep the temperature for reaction for 2 hours, add DMF to reduce viscosity, cool to 35°C, add TEA for neutralization for 25 minutes, add deionized water at a speed of 2000 r / min, add deionized water solution mixed with EDA after dispersion, continue to disperse for 12 minutes, add the waterborne polyurethane emulsion in step (1), evenly distribute it on a polytetrafluoroethylene plate by casting, dry it at room temperature for 35 hours, and then dry it at 65°C for 25 hours to obtain a waterborne polyurethane of TNO (WPU-TNO), completely remove DMF and water to obtain a coating film with uniform thickness, and put it into a dryer for use; Step (3) Preparation of antibacterial and antifungal fatliquor by esterification reaction The molar ratio of oil to alcohol is 2:4, and the molar ratio of the waterborne polyurethane (WPU-TNO) of TNO prepared in step (2) to maleic anhydride is 1:0.7. The esterified oil is placed in a water bath at 65°C, and an aqueous sodium metabisulfite solution is slowly added dropwise using a separatory funnel. After the reaction, the temperature is lowered to 35°C, and the pH value of the fatliquor is adjusted to about 2 with aqueous ammonia to obtain an antibacterial and antifungal fatliquor. Step (4) Preparation of dendritic mesoporous silica 0.6 g of CTAB was dissolved in 65 mL of deionized water, and then 10 mL of ether, 10 mL of ethanol and ammonia water were added. After magnetic stirring for 20 min, 1.5 mL of TEOS and APTES were added dropwise and stirred for 2 h. Then, hydrochloric acid solution was added to adjust the pH value of the solution to 2. The solution was stirred for 10 min again and then centrifuged. The solution was washed twice with ethanol and deionized water respectively, and finally dried at 45 ° C for 2 h to obtain dendritic mesoporous silica. Step (5) Preparation of silica-loaded nanosilver antibacterial agent Prepare 0.001 mol·L -1 Silver nitrate solution, 0.004 mol·L -1 of sodium borohydride solution for later use; take 25 mg of the dendritic mesoporous silica prepared in step (4) and disperse it in 15 mL of ethanol, and ultrasonicate for 65 min; take 15 mL of silver nitrate solution and add it to the ethanol solution, shade the reaction for 3 h, then disperse 2 mg of PVP-K30 in 12 mL of deionized water, and then add it dropwise to the reaction solution, and stir for 16 min; then take 6 mL of sodium borohydride solution and add it dropwise to the reaction solution; immediately centrifuge after the addition, and wash twice with ethanol and deionized water respectively; finally freeze-dry for 12 h to obtain a silica-loaded nanosilver antibacterial agent; Step (6) Preparation of Nano-TiO2 Self-cleaning Hydrosol Dissolve butyl titanate in anhydrous ethanol to form a mixed solution of butyl titanate and ethanol; add 35% hydrochloric acid to distilled water to obtain a hydrochloric acid aqueous solution with a pH of 1.5; then drip the butyl titanate and ethanol mixed solution into the hydrochloric acid aqueous solution at a rate of 1.0 drop / s under stirring; continue stirring for 2 hours after the dropwise addition to obtain a milky white aqueous dispersion; finally seal the solution and allow it to stand for aging to form a slightly yellowish translucent nano-TiO2 hydrosol; Step (7) Preparation of silica-loaded nanosilver / TiO2 self-cleaning / WPU-TNO antibacterial coating The silica-loaded nano-silver antibacterial agent prepared in step (5) and the nano-TiO2 self-cleaning hydrosol prepared in step (6) are ultrasonically dispersed in deionized water, and then the antibacterial and mildew-proof fatliquor prepared in step (3) is added, and the polyurethane dispersion is slowly dripped into the reaction system, and then deionized water is added, stirred until the mixture is uniform, and then emulsified, and acetone is removed by vacuum distillation; thus, the silica-loaded nano-silver / TiO2 self-cleaning / WPU-TNO antibacterial coating is obtained.

[0034] Comparison of detection experiments: The silicon oxide loaded nanosilver / TiO2 self-cleaning / WPU-TNO antibacterial coatings obtained in Examples 1 to 4 and the comparative products 1 and 2 were tested. The specific testing method is as follows: UV-Vis spectroscopy Firstly, Rhodamine B with a concentration of 100 mg / L was used as the adsorption liquid to adsorb the nano-TiO2 finished polyester fabric. Then, the self-cleaning performance of the nano-TiO2 finished polyester fabric was tested. The fabric was taken out at regular intervals and immersed in 20 mL of distilled water at a temperature of 50°C to fully extract the dye on the surface of the fabric to completely dissolve in the aqueous solution. Finally, the extract was collected and the change of the dye absorption peak intensity was measured in the range of 200-800 nm using a UV-1800 spectrophotometer. The scanning step was 2 nm and the scanning frequency was 480 nm min. -1 Antibacterial coating film antibacterial test Take a loopful of the second generation activated bacteria and put it into a 30 mL sterilized nutrient broth culture dish, place it in a vacuum drying oven at 37°C for 24 h, and dilute it with deionized water to a concentration of 1.5 x 10 8 CFU / mL; the silica-loaded nanosilver / TiO2 self-cleaning / WPU-TNO antibacterial coating was coated on a 5cm x 5cm glass slide, and after it dried to form a film, 0.5mL1.5 x 10 8Drop the bacterial suspension of CFU / mL onto the coated glass slide, cover with sterilized plastic wrap, place the glass slide in a culture dish, and culture at 37°C for 24 hours. After 24 hours, separate the plastic wrap and glass slide, place in a beaker with 100mL deionized water, and wash. Use sterilized tweezers to remove the glass slide and plastic wrap.

[0035] Table 1 Adsorption performance

[0036] As can be seen from Table 1, Example 4 is the best, and Comparative Example 2 is relatively poor. In the examples, more functional groups can be introduced by APTES modification to improve the adsorption capacity of silica for nano-silver antibacterial agents. This high adsorption performance helps to form a stable antibacterial agent loading system in the coating. The better the adsorption capacity, the more uniform the distribution of each component in the coating can be ensured to form a stable system, thereby improving the antibacterial, mildew-proof and self-cleaning functions of the coating.

[0037] Table 2 Self-cleaning performance

[0038] As can be seen from Table 2, Example 4 is the best, while Comparative Example 2 is relatively poor. The concentration of TiO2 in the examples will affect its dispersibility and photocatalytic performance in the hydrosol. The excellent adsorption performance helps the uniform distribution of nano-TiO2 in the coating to form an effective photocatalytic interface, thereby improving the self-cleaning effect of the coating. The dye concentration in Example 4 is the lowest, while the dye concentration in Comparative Example 2 is the highest. As the dye concentration increases, the difficulty of cleaning will also increase accordingly.

[0039] Table 3 Antibacterial properties

[0040] As can be seen from Table 3, Example 4 is the best, and Comparative Example 2 is relatively poor. Example 4 has the best antibacterial rate, because the antibacterial component in the antibacterial and mildew-proof fatliquor in the example can synergize with nanosilver and has the best effect, thereby improving the overall antibacterial performance of the coating, and the film-forming property and density of the prepared coating affect the distribution and release of the antibacterial component in the coating. The coating with good film-forming property and high density prepared by the example can better protect the antibacterial component.

[0041] This specific embodiment is merely an explanation of the present invention and is not a limitation of the present invention. After reading this specification, those skilled in the art can make non-creative modifications to the present embodiment as needed, but they are protected by patent law as long as they are within the scope of the claims of the present invention.

Claims

1. A preparation process of a mildew-proof, antibacterial and self-cleaning coating, characterized in that: include: Preparation of water-based polyurethane emulsion, synthesis of water-based polyurethane of TNO (WPU-TNO), preparation of antibacterial and antifungal fatliquor by esterification reaction, preparation of dendritic mesoporous silica, APTES-modified dendritic mesoporous silica, preparation of silica-loaded nanosilver antibacterial agent, preparation of nano-TiO2 self-cleaning hydrosol, preparation of silica-loaded nanosilver / TiO2 self-cleaning / WPU-TNO antibacterial coating.

2. The preparation process of a mildew-proof, antibacterial and self-cleaning coating according to claim 1, characterized in that: Step (1) Preparation of waterborne polyurethane emulsion Add polypropylene glycol and isophorone diisocyanate into a three-necked flask and stir to perform a prepolymerization reaction, then lower the system temperature, add acetone, then add a catalyst dibutyltin dilaurate, then mix dimethylolpropionic acid and 1,4-butanediol evenly and add them to the reaction system in four times, then titrate the isocyanate with dibutylamine, add TEA (triethylamine) to neutralize the emulsion; add deionized water, add EDA (ethylenediamine) after the emulsification is even, stir to obtain a WPU (waterborne polyurethane) emulsion; finally, evaporate the acetone by vacuum distillation to obtain an acetone-free waterborne polyurethane emulsion; Step (2) Synthesis of waterborne polyurethane of TNO (WPU-TNO) IPDI (isophorone diisocyanate), polyester polyol and DBTDL (isophorone diisocyanate) are added to a three-necked flask with mechanical stirring, and after the reaction, BDO (1,4-butanediol) and DMPA (2,2-bis(hydroxymethyl)propionic acid) are added, and TNO (hexahydro-1,3,5-tris(hydroxyethyl)-s-triazine) is used for chain extension, and DMF (N,N-dimethylformamide) is added to reduce the viscosity after the temperature is maintained for reaction, and TEA is added for neutralization after the temperature is lowered, and deionized water is added, and after dispersion, a deionized water solution of mixed EDA (anhydrous ethylenediamine) is added, and the water-based polyurethane emulsion of step (1) is added and evenly distributed on a polytetrafluoroethylene plate by casting, and a film is formed and dried at room temperature, and then a water-based polyurethane (WPU-TNO) of TNO is obtained by drying, and DMF and water are completely removed to obtain a coating film with uniform thickness, which is placed in a dryer for standby use; Step (3) Preparation of antibacterial and antifungal fatliquor by esterification reaction Add the waterborne polyurethane (WPU-TNO) of TNO prepared in step (2) and maleic anhydride, place the esterified oil in a water bath, slowly add a sodium metabisulfite aqueous solution dropwise with a separatory funnel, cool after the reaction, and adjust the pH value of the fatliquor to a certain value with ammonia water to obtain an antibacterial and antifungal fatliquor; Step (4) Preparation of dendritic mesoporous silica CTAB (hexadecyltrimethylammonium bromide) was dissolved in deionized water, and then ether, ethanol and ammonia water were added. After magnetic stirring, TEOS (tetraethyl orthosilicate) and APTES (3-aminopropyltriethoxysilane) were added dropwise and stirred, and then hydrochloric acid solution was added to adjust the pH, stirred again, and then the obtained solution was centrifuged, washed with ethanol and deionized water respectively, and finally dried to obtain dendritic mesoporous silica; Step (5) APTES modified dendritic mesoporous silica Disperse the dendritic mesoporous silica prepared in step (4) in toluene and perform ultrasonic treatment. Take a round-bottom flask, add the silica dispersion into the flask and then drop APTES into the flask. Centrifuge with magnetic stirring, separate, wash and dry to obtain modified dendritic mesoporous silica. Step (6) Preparation of silica-loaded nanosilver antibacterial agent Add silver nitrate solution and sodium borohydride solution, take the dendritic mesoporous silica modified in step (5), disperse it in ethanol and perform ultrasonic treatment; take the silver nitrate solution and add it to the ethanol solution, after the light shielding reaction, disperse PVP-K30 (polyvinyl pyrrolidone K30) in deionized water, and then add it dropwise to the reaction solution and stir; then take the sodium borohydride solution and add it dropwise to the reaction solution; immediately centrifuge after the addition, and wash with ethanol and deionized water; finally freeze-dry to obtain a silica-loaded nanosilver antibacterial agent; Step (7) Preparation of Nano-TiO2 Self-cleaning Hydrosol Dissolving butyl titanate in anhydrous ethanol to form a mixed solution of butyl titanate and ethanol; adding hydrochloric acid to distilled water to obtain a hydrochloric acid aqueous solution; then dripping the hydrochloric acid aqueous solution into the mixed solution of butyl titanate and ethanol under stirring; continuing to stir after the dripping is completed to obtain a milky white aqueous dispersion; finally sealing and letting it stand for aging to form a slightly yellowish translucent nano-TiO2 hydrosol; Step (8) Preparation of silica-loaded nanosilver / TiO2 self-cleaning / WPU-TNO antibacterial coating The silica-loaded nano-silver antibacterial agent prepared in step (6) and the nano-TiO2 self-cleaning hydrosol prepared in step (7) are ultrasonically dispersed in deionized water, and then the antibacterial and mildew-proof fatliquor prepared in step (3) is added, and the polyurethane dispersion is slowly dripped into the reaction system, and then deionized water is added, stirred until the mixture is uniform, and then emulsified, and acetone is removed by vacuum distillation; thus, the silica-loaded nano-silver / TiO2 self-cleaning / WPU-TNO antibacterial coating is obtained.

3. The preparation process of a mildew-proof, antibacterial and self-cleaning coating according to claim 2, characterized in that: Step (1) Preparation of waterborne polyurethane emulsion Add polypropylene glycol and isophorone diisocyanate into a three-necked flask and stir, and perform prepolymerization at 80-85°C for 90-100 minutes; then lower the system temperature to 80-85°C, add acetone, and then add 6-7 drops of catalyst dibutyltin dilaurate, and then mix dimethylolpropionic acid and 1,4-butanediol evenly and add them to the reaction system four times (once every 10-15 minutes), react for 95-100 minutes after adding, and then titrate the isocyanate with dibutylamine, and add TEA (triethylamine) to neutralize the emulsion; add deionized water, stir and emulsify, add EDA (ethylenediamine) after the emulsification is uniform, and stir to obtain WPU (waterborne polyurethane) emulsion; finally, evaporate the acetone by vacuum distillation to obtain an acetone-free waterborne polyurethane emulsion.

4. The preparation process of the mildew-proof, antibacterial and self-cleaning coating according to claim 3, characterized in that: Step (2) Synthesis of waterborne polyurethane of TNO (WPU-TNO) Add IPDI (isophorone diisocyanate), polyester polyol and DBTDL (isophorone diisocyanate) into a three-necked flask with mechanical stirring, react for 1-5 hours, then add BDO and DMPA and use TNO for chain extension, keep the temperature for reaction for 1-4 hours, then add DMF to reduce viscosity, cool to 40-45°C, add TEA for neutralization for 30-35 minutes, add deionized water at a speed of 2500-3000 r / min, add deionized water solution mixed with EDA after dispersion, continue to disperse for 10-15 minutes, add the waterborne polyurethane emulsion of step (1), evenly distribute it on a polytetrafluoroethylene plate by casting, dry it at room temperature for 40-48 hours, and then dry it at 70-75°C for 36-45 hours to obtain a waterborne polyurethane of TNO (WPU-TNO), completely remove DMF and water to obtain a coating with uniform thickness, and put it into a dryer for use.

5. The preparation process of a mildew-proof, antibacterial and self-cleaning coating according to claim 4, characterized in that: Step (3) Preparation of antibacterial and antifungal fatliquor by esterification reaction The molar ratio of oil to alcohol is 1-2:2-4, and the molar ratio of the waterborne polyurethane (WPU-TNO) of TNO prepared in step (2) to maleic anhydride is 1-5:0.7-0.

9. The esterified oil is placed in a water bath at 70-75°C, and an aqueous sodium metabisulfite solution is slowly added dropwise using a separatory funnel. After the reaction, the temperature is lowered to 40-45°C, and the pH value of the fatliquor is adjusted to about 1-7 with ammonia water to obtain an antibacterial and anti-mildew type fatliquor.

6. The preparation process of a mildew-proof, antibacterial and self-cleaning coating according to claim 2, characterized in that: Step (4) Preparation of dendritic mesoporous silica Dissolve 0.5-0.9 g of CTAB in 70-75 mL of deionized water, add 15-20 mL of ether, 5-15 mL of ethanol and ammonia water, stir magnetically for 25-30 min, add 2.5-5.5 mL of TEOS and APTES dropwise and stir for 1-4 h, then add hydrochloric acid solution to adjust the pH value of the solution to 1-7, stir again for 15-30 min, then centrifuge the resulting solution, wash with ethanol and deionized water 1-3 times, respectively, and finally dry at 55-60° C. for 1-6 h to obtain dendritic mesoporous silica.

7. The preparation process of the mildew-proof, antibacterial and self-cleaning coating according to claim 6, characterized in that: Step (5) APTES modified dendritic mesoporous silica Take 450-500 mg of the dendritic mesoporous silica prepared in step (4) and disperse it in 50-55 mL of toluene and ultrasonicate for 1-2 hours; take a round-bottom flask, add the silica dispersion into the flask and then drop 2-5 mL of APTES, reflux at 85-95° C., stir magnetically for 15-30 minutes, centrifuge, separate, wash and dry to obtain modified dendritic mesoporous silica.

8. The preparation process of the mildew-proof, antibacterial and self-cleaning coating according to claim 7, characterized in that: Step (6) Preparation of silica-loaded nanosilver antibacterial agent Prepare 0.002-0.006mol·L -1 Silver nitrate solution, 0.005-0.009mol·L -1 The sodium borohydride solution is set aside; 35-40 mg of the dendritic mesoporous silica modified in step (5) is dispersed in 20-25 mL of ethanol and ultrasonicated for 85-90 min; 20-25 mL of silver nitrate solution is added to the ethanol solution, and after shading for 2-10 h, 1-4 mg of PVP-K30 is dispersed in 10-15 mL of deionized water, and then added dropwise to the reaction solution, and stirred for 15-30 min; then 5-10 mL of sodium borohydride solution is added dropwise to the reaction solution; centrifugation is immediately performed after the addition is completed, and the solution is washed with ethanol and deionized water for 1-3 times each; and finally, freeze-dried for 10-15 h to obtain a silica-loaded nanosilver antibacterial agent.

9. The preparation process of a mildew-proof, antibacterial and self-cleaning coating according to claim 8, characterized in that: Step (7) Preparation of Nano-TiO2 Self-cleaning Hydrosol Dissolve butyl titanate in anhydrous ethanol to form a mixed solution of butyl titanate and ethanol; at the same time, add 35-40% hydrochloric acid into distilled water to obtain a hydrochloric acid aqueous solution with a pH of 1.5-2.5; then drip the butyl titanate and ethanol mixed solution into the hydrochloric acid aqueous solution at a rate of 1.0-2.0 drops / s under stirring conditions; after the dropwise addition is completed, continue stirring for 1-5 hours to obtain a milky white aqueous dispersion; finally, seal it and let it stand for aging to form a slightly yellowish translucent nano-TiO2 hydrosol.

10. The preparation process of the mildew-proof, antibacterial and self-cleaning coating according to claim 9, characterized in that: Step (8) Preparation of silica-loaded nanosilver / TiO2 self-cleaning / WPU-TNO antibacterial coating The silica-loaded nano-silver antibacterial agent prepared in step (6) and the nano-TiO2 self-cleaning hydrosol prepared in step (7) are ultrasonically dispersed in deionized water, and then the antibacterial and mildew-proof fatliquor prepared in step (3) is added, and the polyurethane dispersion is slowly dripped into the reaction system, and then deionized water is added, stirred until the mixture is uniform, and then emulsified, and acetone is removed by vacuum distillation; thus, the silica-loaded nano-silver / TiO2 self-cleaning / WPU-TNO antibacterial coating is obtained.

Images