Filler-modified silicone aqueous polyurethane and abrasion-resistant superhydrophobic coating thereof and preparation method thereof

Abstract

This invention belongs to the field of waterborne coatings and discloses a filler-modified organosilicon waterborne polyurethane, its wear-resistant superhydrophobic coating, and its preparation method. The wear-resistant superhydrophobic coating is made by stirring waterborne polyurethane emulsion as the main raw material, adding hydrophobic modified organosilicon, nanofiller modifiers, and additives. This coating not only has excellent adhesion and wear resistance but also superhydrophobic properties. Specifically, the introduction of hydrophobic modified organosilicon improves the coating's adhesion strength to the substrate and its wear resistance; the introduced low surface energy -Si-O-Si segments improve the coating's hydrophobicity, giving it superhydrophobic properties; and different fillers impart good UV resistance and wear resistance to the coating.

Description

Technical Field

[0001] This invention belongs to the field of waterborne coatings, specifically relating to a filler-modified organosilicon waterborne polyurethane and its wear-resistant superhydrophobic coating and preparation method. Background Technology

[0002] Waterborne polyurethane (WPU) coatings are widely used in construction, furniture, and automotive industries due to their environmental friendliness, low VOC emissions, and excellent film-forming properties. However, pure WPU coatings have significant performance shortcomings: insufficient abrasion resistance, making them prone to scratches and wear after long-term use; poor weather resistance, easily aging and yellowing after UV exposure; and a lack of antibacterial properties, making them susceptible to bacterial growth in humid environments, thus limiting their application in outdoor and hygiene-sensitive scenarios.

[0003] In existing technologies, a single filler is often used to modify a specific property of WPU coatings to improve it. For example, adding nano-alumina (Al2O3) enhances wear resistance, but its poor dispersibility and tendency to agglomerate do not improve weather resistance and antibacterial properties. Adding nano-silica (SiO2) optimizes weather resistance, but its low hardness limits its improvement in wear resistance. Adding nano-titanium dioxide (TiO2) achieves photocatalytic antibacterial and weather resistance, but its antibacterial efficiency is limited by light conditions when used alone, and its improvement on the mechanical properties of the coating is not significant. In addition, existing composite filler modification schemes often neglect the synergistic effect between fillers and fail to improve the interfacial compatibility between the filler and the WPU matrix through optimized surface modification processes. This results in limited improvement in the overall performance of the coating, making it difficult to meet the needs of multifunctional coatings in various scenarios.

[0004] Therefore, developing a composite filler modification scheme that can synergistically improve the wear resistance, weather resistance and antibacterial properties of waterborne polyurethane coatings, and that also has uniform filler dispersion and stable interfacial bonding, has become an urgent technical problem to be solved in this field. Summary of the Invention

[0005] In order to overcome the shortcomings and deficiencies of the prior art, such as the inability to uniformly disperse fillers in the polymer matrix and the inability to simultaneously improve the mechanical strength, wear resistance, weather resistance and antibacterial properties of waterborne polyurethane, the primary objective of this invention is to provide a method for preparing filler-modified organosilicon waterborne polyurethane.

[0006] Another objective of this invention is to provide a filler-modified organosilicon waterborne polyurethane prepared by the above-described preparation method.

[0007] Another object of the present invention is to provide a wear-resistant superhydrophobic coating made of the above-mentioned filler-modified organosilicon waterborne polyurethane.

[0008] The objective of this invention is achieved through the following technical solution: A method for preparing filler-modified organosilicon waterborne polyurethane includes the following steps: S1. Add silane coupling agent and triethylamine to TiO2 nanoparticle dispersion, react in a water bath at 25-30℃ for 20-24 hours, and then centrifuge, wash, dry and grind to obtain modified TiO2 powder; add silane coupling agent to nano Al2O3 dispersion, react in a water bath at 75-85℃ for 4-6 hours, and then centrifuge, wash, dry and grind to obtain modified Al2O3 powder; S2. Take hydrophilic vapor-phase nano-SiO2, modified TiO2 powder obtained in step S1, and modified Al2O3 powder, add them to deionized water, and ultrasonically disperse to prepare a slurry. S3, carbon hydroxyl-terminated polydimethylsiloxane is dehydrated under reduced pressure and then isocyanate is added. The mixture is heated for 2 hours under nitrogen protection and with the aid of a catalyst. Then, polytetrahydrofuran, which has been dehydrated under reduced pressure, is added and reacted for 1.5 to 2 hours to obtain the first reaction solution. Polyol and crosslinking agent are added to the first reaction solution and reacted at 70 to 80°C for 1.5 to 2.5 hours to obtain the second reaction solution. S4. After cooling the second reaction liquid obtained in step S3, add the chain extender after neutralization and emulsification and react for 0.5 hours. Then add the slurry obtained in step S2 and stir to obtain filler-modified organosilicon waterborne polyurethane.

[0009] The TiO2 nanoparticle dispersion mentioned in step S1 is prepared by adding nano-TiO2 to anhydrous ethanol at a mass-volume ratio of 1g:(50~60)mL, dispersing it ultrasonically, and then adjusting the pH value to 3~5; the nano-Al2O3 dispersion is prepared by adding nano-Al2O3 to anhydrous ethanol at a mass-volume ratio of 1g:(50~60)mL, dispersing it ultrasonically, and then adjusting the pH value to 3~5. The silane coupling agent is KH-550; The mass ratio of nano-TiO2 to silane coupling agent and triethylamine in the TiO2 nanoparticle dispersion is 1:(0.8-1.0):(1.3-1.8); the mass ratio of nano-Al2O3 to silane coupling agent in the nano-Al2O3 dispersion is 1:(0.8-1.0).

[0010] The mass ratio of the hydrophilic vapor-phase nano-SiO2, modified TiO2 powder and modified Al2O3 powder in step S2 is 0.05:0.2:(0.2~0.6).

[0011] In step S3, the mass ratio of the carbon hydroxyl-terminated polydimethylsiloxane, polytetrahydrofuran, isocyanate, crosslinking agent, and polyol is (0.5~1.0):(9~12):(6.7~7.5):(0.25~0.45):(1.39~1.65). The isocyanate is toluene diisocyanate; The polyol is 1,4-butanediol and dimethylolbutyric acid; The crosslinking agent is trimethylolpropane; The catalyst is dibutyltin dilaurate.

[0012] In step S3, the dehydration conditions for the carbon hydroxyl-terminated polydimethylsiloxane and polytetrahydrofuran are both vacuum dehydration at 110-120°C for 3-4 hours; the addition of isocyanate is carried out at 70-80°C; and the addition of polyol and crosslinking agent is carried out at 70-80°C.

[0013] The chain extender mentioned in step S4 is ethylenediamine; The mass ratio of the isocyanate in step S3 to the chain extender in step S4 is (6.7-7.5):(1.0-1.2). The mass ratio of the slurry used in step S4 to the isocyanate mentioned in step S3 is (0.1-1.1):(6.7-7.5).

[0014] In step S4, the second reaction solution is cooled and then subjected to neutralization and emulsification, specifically according to the following steps: the second reaction solution is cooled to 30-40°C, triethylamine is added for neutralization, and then deionized water is added and stirred for emulsification; the mass ratio of triethylamine to isocyanate in step S3 is (0.77-0.85):(6.7-7.5); the volume-mass ratio of deionized water to isocyanate in step S3 is (40-44) mL:(6.7-7.5) g.

[0015] A filler-modified organosilicon waterborne polyurethane prepared by the above preparation method.

[0016] A wear-resistant superhydrophobic coating is prepared by curing the above-mentioned filler-modified organosilicon waterborne polyurethane into a film.

[0017] The coating has a tensile strength of 14.65–35.40 MPa, a water absorption rate of 4.55–13.31%, an abrasion mass loss of 1.86–5.32 mg, and a sand abrasion resistance of 16.71–26.04 L / μm.

[0018] Compared with the prior art, the present invention has the following advantages and beneficial effects: (1) The wear-resistant superhydrophobic coating prepared by the present invention is made by adding hydrophobic modified organosilicon, nanofiller modifier, defoamer and other additives as the main raw material and stirring. The coating not only has excellent adhesion and wear resistance, but also has superhydrophobic effect. Among them, the introduction of hydrophobic modified organosilicon improves the coating's bonding strength and wear resistance to the substrate, and the introduced low surface energy -Si-O-Si segments improve the coating's hydrophobicity and give it superhydrophobic properties. Different fillers give the coating good UV resistance and wear resistance.

[0019] (2) The product of the present invention has properties such as UV resistance, wear resistance and superhydrophobicity, and has broad application prospects. Attached Figure Description

[0020] Figure 1 These are the infrared spectra of nano-TiO2 and nano-Al2O3 before and after modification in this invention; Figure 2 These are contact angle test diagrams of the coatings obtained in Comparative Example 1 and Example 3 of the present invention; Figure 3 These are test graphs showing the wear resistance of the coatings obtained in all embodiments and Comparative Example 1. Detailed Implementation

[0021] To make the objectives, technical solutions, and advantages of this invention clearer, the invention will be further described in detail below with reference to the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are merely illustrative and not intended to limit the invention.

[0022] To address the shortcomings of existing technologies, such as the difficulty in uniformly dispersing nanofillers in polymer matrices like waterborne polyurethane, and the fact that existing technologies often only improve certain properties of waterborne polyurethane (such as mechanical strength, water resistance, or abrasion resistance), this invention provides a method for preparing composite filler-modified waterborne polyurethane. By combining a silane coupling agent with the hydroxyl groups on the filler surface, high dispersibility of the filler in SWPU (silicone-modified waterborne polyurethane) is achieved. Simultaneously, the waterborne polyurethane coating exhibits high mechanical strength, excellent water resistance, resistance to wind and sand impact, and abrasion resistance, achieving a balance between the two.

[0023] In a first aspect, the present invention provides a method for preparing filler-modified organosilicon waterborne polyurethane, comprising the following steps: S1. Add silane coupling agent and triethylamine to TiO2 nanoparticle dispersion, react in a water bath at 25-30℃ for 20-24 hours, and then centrifuge, wash, dry and grind to obtain modified TiO2 powder; add silane coupling agent to nano Al2O3 dispersion, react in a water bath at 75-85℃ for 4-6 hours, and then centrifuge, wash, dry and grind to obtain modified Al2O3 powder.

[0024] S2, take a certain proportion of hydrophilic vapor-phase nano-SiO2, modified TiO2 powder obtained in step S1 and modified Al2O3 powder, add them to deionized water and ultrasonically disperse to prepare a slurry.

[0025] S3, carbon hydroxyl-terminated polydimethylsiloxane is dehydrated under reduced pressure and then isocyanate is added. The mixture is heated for 2 hours under nitrogen protection and with the help of a catalyst. Then, polytetrahydrofuran, which has been dehydrated under reduced pressure, is added and reacted for 2 hours to obtain the first reaction solution. Polyol and crosslinking agent are added to the first reaction solution and reacted at 70-80°C for 1.5-2.5 hours to obtain the second reaction solution.

[0026] S4. After cooling the second reaction liquid obtained in step S3, add the chain-linking agent after neutralization and emulsification and react for 0.5 hours. Then add the slurry obtained in step S2 and stir to obtain filler-modified organosilicon waterborne polyurethane.

[0027] This invention leverages the inherent properties of the material by functionalizing the filler surface with a silane coupling agent. The hydroxyl groups on the filler react with the silane coupling agent, and after successful grafting, the original hydrophilic inorganic properties of the nanofiller surface are covered by the organic functional groups (-NH2) at the other end of the coupling agent. This significantly improves compatibility with organic polymers and effectively prevents aggregation between filler particles caused by hydrogen bonding. The three fillers function separately: nano-TiO2 provides UV resistance and antibacterial properties, nano-Al2O3 provides high strength and hardness, and nano-SiO2 provides water resistance and acts as a thickener; significantly improving the mechanical strength, water resistance, and wear resistance of the coating.

[0028] Preferably, in step S1, the TiO2 nanoparticle dispersion is prepared by adding nano-TiO2 to anhydrous ethanol at a mass-volume ratio of 1g:(50~60)mL, dispersing it ultrasonically, and then adjusting the pH value to 3~5; the nano-Al2O3 dispersion is prepared by adding nano-Al2O3 to anhydrous ethanol at a mass-volume ratio of 1g:(50~60)mL, dispersing it ultrasonically, and then adjusting the pH value to 3~5; specifically, the pH value is adjusted to 3.0, 3.5, 4.0, 4.5, or 5.0; the ratio between nanoparticles and anhydrous ethanol includes, but is not limited to, 1g:50mL, 1g:52mL, 1g:55mL, 1g:56mL, 1g:58mL, 1g:60mL, etc.

[0029] Preferably, in step S1, the silane coupling agent includes γ-aminopropyltriethoxysilane (KH-550).

[0030] Preferably, in step S1, the mass ratio of nano-TiO2 to silane coupling agent in the TiO2 nanoparticle dispersion is 1:(0.8-1.0); the mass ratio of nano-Al2O3 to silane coupling agent in the nano-Al2O3 dispersion is 1:(0.8-1.0), and this mass ratio includes, but is not limited to, 1:0.8, 1:0.85, 1:0.9, 1:0.95, 1:1.0, etc. The mass ratio of nano-TiO2 to triethylamine in the TiO2 nanoparticle dispersion is 1:(1.3-1.8), and this mass ratio includes, but is not limited to, 1:1.3, 1:1.4, 1:1.5, 1:1.6, 1:1.7, 1:1.8, etc.

[0031] Preferably, in step S1, the reaction is carried out in a water bath at 25~30℃ for 20~24 hours. The water bath temperature during this process includes, but is not limited to, 25℃, 26℃, 27℃, 28℃, 30℃, etc., and the time includes, but is not limited to, 20h, 21h, 22h, 23h, 24h, etc.; or in a water bath at 75~85℃ for 4~6 hours. The water bath temperature during this process includes, but is not limited to, 75℃, 78℃, 80℃, 82℃, 85℃, etc., and the time includes, but is not limited to, 4h, 4.5h, 5h, 5.5h, 6h, etc.

[0032] Preferably, in step S1, the washing liquid includes ethanol and deionized water.

[0033] Preferably, in step S2, the mass ratio of hydrophilic vapor-phase nano-SiO2, modified TiO2 powder and modified Al2O3 powder is 0.05:0.2:(0.2~0.6).

[0034] Preferably, in step S3, the dehydration temperature of the carbon hydroxyl-terminated polydimethylsiloxane and polytetrahydrofuran under reduced pressure is 110–120°C, and the time is 3–4 hours. Specifically, the dehydration temperature includes, but is not limited to, 110°C, 113°C, 116°C, 119°C, and 120°C; the time includes, but is not limited to, 3 hours, 3.5 hours, and 4 hours.

[0035] Preferably, in step S3, the mass ratio of the carbon hydroxyl-terminated polydimethylsiloxane, polytetrahydrofuran, isocyanate, crosslinking agent, and polyol is (0.5~1.0):(9~12):(6.7~7.5):(0.25~0.45):(1.39~1.65); specifically, this mass ratio includes, but is not limited to, 0.5:10:7.2:0.25:1.39, 0.8:12:7.5:0.30:1.45, 1.0:9:7.0:0.35:1.55, 0.6:11:6.7:0.40:1.60, 0.9:10:7.5:0.45:1.65, etc.

[0036] Preferably, in step S3, the isocyanate includes toluene diisocyanate; the polyol includes 1,4-butanediol and dimethylolbutyric acid; the crosslinking agent is trimethylolpropane; and the catalyst includes dibutyltin dilaurate.

[0037] Preferably, in step S3, after dehydration under reduced pressure, the carbon hydroxyl-terminated polydimethylsiloxane is reacted with isocyanate at 75-80°C for 2 hours, followed by the addition of dehydrated polytetrahydrofuran at 75-80°C for 2 hours. The heating temperature for adding isocyanate or polytetrahydrofuran is 75-80°C, and the reaction time is 2 hours. Specifically, the reaction temperatures for adding isocyanate and polyol include, but are not limited to, 75°C, 76°C, 78°C, 79°C, and 80°C; the heating temperatures for adding chain extender include, but are not limited to, 70°C, 72°C, 75°C, 78°C, and 80°C.

[0038] Preferably, in step S4, the chain extender includes trimethylolpropane and ethylenediamine.

[0039] Preferably, the mass ratio of the isocyanate in step S3 to the chain extender in step S4 is (6.7-7.5):(1.0-1.2), including but not limited to 6.7:1.0, 6.7:1.2, 7.0:1.1, 7.2:1.2, 7.0:1.0, 7.5:1.2, etc.

[0040] Preferably, the mass ratio of the slurry used in step S4 to the isocyanate mentioned in step S3 is (0.1-1.1):(6.7-7.5).

[0041] Preferably, in step S3, the second reaction solution is cooled and then subjected to neutralization and emulsification, specifically according to the following steps: the second reaction solution is cooled to 30-40°C, triethylamine is added for neutralization, and then deionized water is added and stirred for emulsification. The volume-to-mass ratio of the deionized water to the isocyanate in step S3 is (40-44) mL: (6.7-7.5) g.

[0042] More preferably, the mass ratio of triethylamine to isocyanate in step S3 is (0.77–0.85):(6.7–7.5); the volume-to-mass ratio of deionized water to isocyanate in step S3 is (40–44) mL:(6.7–7.5) g. Specifically, the mass ratio of triethylamine to isocyanate includes, but is not limited to, 0.80:6.7, 0.85:7.0, 0.77:7.5, 0.85:7.5, 0.85:7.2, etc.; the ratio of deionized water to isocyanate includes, but is not limited to, 40 mL:6.8 g, 41 mL:6.8 g, 42 mL:7.4 g, 43 mL:7.5 g, 44 mL:7.5 g, etc.

[0043] Secondly, the present invention provides a filler-modified organosilicon waterborne polyurethane prepared by the above preparation method.

[0044] Thirdly, the present invention provides a wear-resistant superhydrophobic coating, which is prepared by curing the above-mentioned filler-modified organosilicon waterborne polyurethane into a film.

[0045] This invention utilizes silane coupling agents to functionalize the surface of fillers. As a highly efficient surface modifier, the silane coupling agent reacts with the hydroxyl groups on the filler. After successful grafting, the original hydrophilic inorganic properties of the nanofiller surface are covered by the organic functional groups (-NH2) at the other end of the coupling agent. This significantly improves compatibility with organic polymers and effectively prevents agglomeration of filler particles caused by hydrogen bonding. It connects to waterborne polyurethane through chemical bonds, increasing the interfacial crosslinking density. Simultaneously, the combination of electrostatic and hydrogen bonding enhances its dispersion stability and interfacial strengthening effect in SWPU. Three fillers function separately: nano-TiO2 provides UV resistance and antibacterial properties, nano-Al2O3 provides high strength and hardness, and nano-SiO2 provides water resistance and acts as a thickener. This significantly improves the mechanical strength, water resistance, and abrasion resistance of the coating.

[0046] The present invention will be further described in detail below with reference to specific embodiments, but the implementation of the present invention is not limited thereto. For process parameters not specifically noted, conventional techniques can be referred to.

[0047] Example 1

[0048] A method for preparing a filler-modified organosilicon waterborne polyurethane wear-resistant superhydrophobic coating includes the following steps: S1. Place 1g of nano-TiO2 in an Erlenmeyer flask, add 50mL of anhydrous ethanol, and sonicate for 40 minutes. Continue to stir magnetically at room temperature for 1 hour. Then, slowly add 1mL of KH-550 and 1.5mL of triethylamine to the above solution. Reflux the mixed solution with stirring for 24 hours. After the reaction is complete, centrifuge, wash, dry at 60℃, and grind to obtain a white TiO2 / KH-550 powder sample for later use. Take 1g of nano Al2O3 and place it in an Erlenmeyer flask. Add 50mL of anhydrous ethanol and sonicate for 40 minutes to disperse it. Then add 1g of silane coupling agent KH-550 and an appropriate amount of deionized water and place them in a beaker. Let them stand for 10 minutes and adjust the pH value to about 3-5 with glacial acetic acid solution. Then pour the KH-550 solution into the Al2O3 slurry and mix. Heat to about 75℃ and stir at a constant temperature of 800r / min for 4 hours. After the reaction is completed, centrifuge, wash, and dry in an oven (80℃) for 12 hours. Grind to obtain a white powder sample of Al2O3 / KH-550 for later use.

[0049] S2, take 0.05g of hydrophilic vapor-phase nano-SiO2, 0.2g of TiO2 / KH-550 and 0.2 Al2O3 / KH-550, add 5mL of deionized water and ultrasonically disperse for 30 minutes to prepare a slurry.

[0050] S3, carbon hydroxyl-terminated polydimethylsiloxane and polytetrahydrofuran were dehydrated under reduced pressure at 110 °C for 4 h, and then cooled to 75 °C. 0.8 g of the dehydrated carbon hydroxyl-terminated polydimethylsiloxane was placed in a three-necked flask, and 6.88 g of toluene diisocyanate and one drop of dibutyltin dilaurate were added. Nitrogen gas was introduced, and the reaction was carried out for 2 h. Then, 10.5 g of the dehydrated polytetrahydrofuran was added, and the reaction was continued for 2 h to obtain the first reaction solution. 0.42 g of 1,4-butanediol and 1.14 g of dimethylolbutyric acid were added to the first reaction solution, and the reaction was carried out for 1 h. Then, 0.42 g of trimethylolpropane was added, and the reaction was continued for another 1 h (during which time the viscosity of the reaction system was monitored and adjusted with acetone) to obtain the second reaction solution. S4, the second reaction solution is cooled to 35℃, 0.778g of triethylamine is added and reacted for 20min, then 44ml of deionized water is added, and the speed is adjusted to 1000rpm, and the mixture is stirred at high speed for 1h. After emulsification, 0.85g of ethylenediamine is added and reacted for 0.5h. Then the slurry obtained in step S2 is added and the mixture is stirred for another 0.5h to obtain filler-modified organosilicon waterborne polyurethane. S5, 15g of filler-modified silicone waterborne polyurethane was weighed and spread evenly onto a polytetrafluoroethylene mold to ensure uniform dispersion. The mixture was left at room temperature for 24 hours and then cured at 60℃ for two days to form a film, resulting in a wear-resistant superhydrophobic coating of filler-modified silicone waterborne polyurethane, denoted as KA / SWPU-2%. Tensile properties, water resistance, abrasion resistance, and wind and sand impact resistance were tested, and the results are shown in Table 1.

[0051] Example 2

[0052] Compared with Example 1, the only difference is that in S2, 0.05g of hydrophilic vapor-phase nano-SiO2, 0.2g of TiO2 / KH-550 and 0.3g of Al2O3 / KH-550 are used to prepare a slurry with an Al2O3 / KH-550 content of 3%. Other steps and conditions are the same as in Example 1. The final coating is denoted as KA / SWPU-3%.

[0053] Example 3

[0054] Compared with Example 1, the only difference is that in S2, 0.05g of hydrophilic vapor-phase nano-SiO2, 0.2g of TiO2 / KH-550 and 0.4g of Al2O3 / KH-550 are used to prepare a slurry with an Al2O3 / KH-550 content of 4%. The other steps and conditions are the same as in Example 1, and the final coating is denoted as KA / SWPU-4%.

[0055] Example 4

[0056] Compared with Example 1, the only difference is that in S2, 0.05g of hydrophilic vapor-phase nano-SiO2, 0.2g of TiO2 / KH-550 and 0.5g of Al2O3 / KH-550 are used to prepare a slurry with an Al2O3 / KH-550 content of 5%. Other steps and conditions are the same as in Example 1. The final coating is denoted as KA / SWPU-5%.

[0057] Example 5

[0058] Compared with Example 1, the only difference is that in S2, 0.05g of hydrophilic vapor-phase nano-SiO2, 0.2g of TiO2 / KH-550 and 0.6g of Al2O3 / KH-550 are used to prepare a slurry with an Al2O3 / KH-550 content of 6%. Other steps and conditions are the same as in Example 1. The final coating is denoted as KA / SWPU-6%.

[0059] Comparative Example 1 Compared with Example 1, the only difference is that S1 and S2 are removed, and no carbon hydroxyl-terminated polydimethylsiloxane is added in S3, that is, no nanofiller and organosilicon are added. The other steps and conditions are the same as in Example 1, and the final coating is denoted as SWPU.

[0060] Comparative Example 2 Compared with Example 1, the only difference is that nano TiO2 and nano Al2O3 are not added, while the other steps and conditions are the same as in Example 1.

[0061] Comparative Example 3 Compared with Example 1, the only difference is that nano-TiO2 is not added, while the other steps and conditions are the same as in Example 1.

[0062] Comparative Example 4 Compared with Example 1, the only difference is that nano-Al2O3 is not added, while the other steps and conditions are the same as in Example 1.

[0063] Performance testing Figure 1 The infrared spectra of nano-TiO2, nano-Al2O3, and KH-550 modified (TiO2 / KH-550 and Al2O3 / KH-550 obtained by modifying nano-TiO2 and nano-Al2O3 according to step S1 of Example 1, respectively) are provided by [the original text is missing]. Figure 1 It can be seen that, after modification, nano-TiO2 at 3400 cm⁻¹ -1 The surface hydroxyl peak intensity drops sharply and becomes a broad peak, reflecting the NH stretching vibration, with peaks appearing at 2930 and 2870 cm⁻¹. -1 A new peak in CH stretching vibration was observed at 1100 cm⁻¹.-1 The formation of clear Si-O-Ti characteristic absorption indicates that KH-550 has largely consumed the surface Ti-OH and formed a stable covalent layer, with high coupling density, indicating successful modification. The 3400 cm⁻¹ of nano-Al₂O₃ further supports this. -1 The peak showed a significant increase, at 2930 cm⁻¹ -1 It shows a faint acromion and a height of 1030 cm. -1 The identifiable weak Si-O-Al peaks enable partial modification.

[0064] Figure 2 The contact angle test results show that, compared to Comparative Example 1, the hydrophobicity of Example 1 was significantly improved after adding carbon hydroxyl-terminated polydimethylsiloxane (from 68.4° to 103.5°). The contact angle of the SWPU composite membrane gradually increased with the increase of composite filler content. In Example 3, the contact angle reached 111.3°, achieving a good hydrophobic effect.

[0065] Mechanical properties of the coating samples obtained from the above examples and comparative examples were tested according to Chapter 9 of GB / T 16777-2008; water absorption was tested according to GB / T 19250-2013; abrasion resistance was tested using the American ASTM D4060 standard. The samples were placed on the sample stage of the abrasion tester, and the abrasion test was conducted at 500g and 1000r. The mass of the sample after the test was measured, and the mass loss was calculated; abrasion resistance was tested using the falling sand method (GB / T23988-2009), using 30-40 mesh quartz sand for falling impact until the substrate with a diameter of 4 mm was gradually worn away, and the required amount of falling sand was recorded. Abrasion resistance (A) is usually expressed in liters per micrometer (L / μm). The results are shown in Table 1 below. Figure 3 As shown.

[0066] Figure 3 For abrasion resistance testing, including sand drop test and Taber abrasion test, by Figure 3As can be seen, compared to Comparative Example 1, the wear resistance of Example 1 was also improved after adding carbon hydroxyl-terminated polydimethylsiloxane (from 16.71 L / μm to 19.47 L / μm). With the addition of nano-SiO2 / TiO2 / Al2O3, there were significant changes in wear resistance and wear mass loss, indicating that the introduction of nano-SiO2 / TiO2 / Al2O3 has a certain promoting effect on the wear resistance of the coating. Furthermore, with the increase of nano-SiO2 / TiO2 / Al2O3 content, the wear resistance increased accordingly, and the wear mass loss gradually decreased and then tended to stabilize. In Example 5, the coating mass loss was only 1.86 mg, and the wear resistance was 26.04 L / μm, which was 65.0% lower than that of Comparative Example 1, and the wear resistance was 55.8% higher. This is mainly due to the high hardness provided by nano-Al2O3 and the low surface energy of organosilicon. The nanofiller acts in the polyurethane system to provide high strength and high hardness, thereby effectively achieving wear resistance.

[0067] Table 1 Performance test of the coating

[0068] As shown in Table 1, the tensile strength of the composite coating obtained in Example 4 reached 35.40 MPa, which is 2.4 times higher than that of the original SWPU (14.65 MPa) in Comparative Example 1. This process reduced the water absorption rate by 63.11%.

[0069] In summary, this invention utilizes silane coupling agents to functionalize the surface of fillers. As a highly efficient surface modifier, the silane coupling agent reacts with the hydroxyl groups on the filler. After successful grafting, the original hydrophilic inorganic properties of the nanofiller surface are covered by the organic functional groups (-NH2) at the other end of the coupling agent. This significantly improves compatibility with organic polymers and effectively prevents agglomeration of filler particles caused by hydrogen bonding. It connects to waterborne polyurethane through chemical bonds, increasing the interfacial crosslinking density. Simultaneously, the combination of electrostatic and hydrogen bonding enhances its dispersion stability and interfacial strengthening effect in SWPU. The three fillers function separately: nano-TiO2 provides UV resistance and antibacterial properties, nano-Al2O3 provides high strength and high hardness, and nano-SiO2 provides water resistance and acts as a thickener. This significantly improves the mechanical strength, water resistance, and abrasion resistance of the coating. In the process of preparing the coating, the nanofiller in the modified silicone waterborne polyurethane provides high strength and high hardness in the polyurethane system, thereby effectively achieving wear resistance. The coating prepared by the modified silicone waterborne polyurethane of this invention has strong mechanical properties (tensile strength can reach 14.65~35.40MPa), good water resistance (water absorption rate is only 4.55~13.31%) and excellent wear resistance (wear mass loss is 1.86~5.32mg, wear resistance is 16.71~26.04L / μm).

[0070] The specific embodiments of the present invention described above do not constitute a limitation on the scope of protection of the present invention. Any other corresponding changes and modifications made in accordance with the technical concept of the present invention should be included within the scope of protection of the claims of the present invention.

Claims

1. A method for preparing filler-modified organosilicon waterborne polyurethane, characterized in that... Includes the following steps: S1. Add silane coupling agent and triethylamine to TiO2 nanoparticle dispersion, react in a water bath at 25-30℃ for 20-24 hours, and then centrifuge, wash, dry and grind to obtain modified TiO2 powder; add silane coupling agent to nano Al2O3 dispersion, react in a water bath at 75-85℃ for 4-6 hours, and then centrifuge, wash, dry and grind to obtain modified Al2O3 powder; S2. Take hydrophilic vapor-phase nano-SiO2, modified TiO2 powder obtained in step S1, and modified Al2O3 powder, add them to deionized water, and ultrasonically disperse to prepare a slurry. S3, carbon hydroxyl-terminated polydimethylsiloxane is dehydrated under reduced pressure and then isocyanate is added. The mixture is heated for 2 hours under nitrogen protection and with the aid of a catalyst. Then, polytetrahydrofuran, which has been dehydrated under reduced pressure, is added and reacted for 1.5 to 2 hours to obtain the first reaction solution. Polyol and crosslinking agent are added to the first reaction solution and reacted at 70 to 80°C for 1.5 to 2.5 hours to obtain the second reaction solution. S4. After cooling the second reaction liquid obtained in step S3, add the chain extender after neutralization reaction and emulsification treatment and stir for 0.5h. Then add the slurry obtained in step S2 and stir to obtain filler-modified organosilicon waterborne polyurethane.

2. The method for preparing filler-modified organosilicon waterborne polyurethane according to claim 1, characterized in that: The TiO2 nanoparticle dispersion mentioned in step S1 is prepared by adding nano-TiO2 to anhydrous ethanol at a mass-volume ratio of 1g:(50~60)mL, dispersing it ultrasonically, and then adjusting the pH value to 3~5; the nano-Al2O3 dispersion is prepared by adding nano-Al2O3 to anhydrous ethanol at a mass-volume ratio of 1g:(50~60)mL, dispersing it ultrasonically, and then adjusting the pH value to 3~5. The silane coupling agent is KH-550; The mass ratio of nano-TiO2 to silane coupling agent and triethylamine in the TiO2 nanoparticle dispersion is 1:(0.8-1.0):(1.3-1.8); the mass ratio of nano-Al2O3 to silane coupling agent in the nano-Al2O3 dispersion is 1:(0.8-1.0).

3. The method for preparing filler-modified organosilicon waterborne polyurethane according to claim 1, characterized in that: The mass ratio of the hydrophilic vapor-phase nano-SiO2, modified TiO2 powder and modified Al2O3 powder in step S2 is 0.05:0.2:(0.2~0.6).

4. The method for preparing filler-modified organosilicon waterborne polyurethane according to claim 1, characterized in that: In step S3, the mass ratio of the carbon hydroxyl-terminated polydimethylsiloxane, polytetrahydrofuran, isocyanate, crosslinking agent, and polyol is (0.5~1.0):(9~12):(6.7~7.5):(0.25~0.45):(1.39~1.65). The isocyanate is toluene diisocyanate; The polyol is 1,4-butanediol and dimethylolbutyric acid; The crosslinking agent is trimethylolpropane; The catalyst is dibutyltin dilaurate.

5. The method for preparing filler-modified organosilicon waterborne polyurethane according to claim 1, characterized in that: In step S3, the dehydration conditions for the carbon hydroxyl-terminated polydimethylsiloxane and polytetrahydrofuran are both 110-120°C for 3-4 hours under reduced pressure; the addition of isocyanate is carried out at 70-80°C; and the addition of polyol and crosslinking agent is carried out at 70-80°C.

6. The method for preparing filler-modified organosilicon waterborne polyurethane according to claim 1, characterized in that: The chain extender mentioned in step S4 is ethylenediamine; The mass ratio of the isocyanate in step S3 to the chain extender in step S4 is (6.7-7.5):(1.0-1.2). The mass ratio of the slurry used in step S4 to the isocyanate mentioned in step S3 is (0.1-1.1):(6.7-7.5).

7. The method for preparing filler-modified organosilicon waterborne polyurethane according to claim 1, characterized in that: In step S4, the second reaction solution is cooled and then subjected to neutralization and emulsification, specifically according to the following steps: the second reaction solution is cooled to 30-40°C, triethylamine is added for neutralization, and then deionized water is added and stirred for emulsification; the mass ratio of triethylamine to isocyanate in step S3 is (0.77-0.85):(6.7-7.5); the volume-mass ratio of deionized water to isocyanate in step S3 is (40-44) mL:(6.7-7.5) g.

8. A filler-modified organosilicon waterborne polyurethane prepared by the preparation method according to any one of claims 1 to 7.

9. A wear-resistant superhydrophobic coating, characterized in that: The wear-resistant superhydrophobic coating is prepared by curing the filler-modified organosilicon waterborne polyurethane of claim 7 into a film.

10. The wear-resistant superhydrophobic coating according to claim 9, characterized in that: The coating has a tensile strength of 14.65–35.40 MPa, a water absorption rate of 4.55–13.31%, an abrasion mass loss of 1.86–5.32 mg, and a sand abrasion resistance of 16.71–26.04 L / μm.

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