A transparent super-hydrophobic coating and its preparation method and application
By fabricating a composite structure of a polyurethane layer and a hydrophobic silica layer on glass, the challenges of high light transmittance and high superhydrophobicity were solved, achieving a self-cleaning effect of the transparent superhydrophobic coating and improving the safety and transparency of the glass.
Patent Information
- Application Number
- CN202310934211.1
- Authority / Receiving Office
- CN · China
- Patent Type
- Patents(China)
- Current Assignee / Owner
- Filing Date
- 2023-07-27
- Publication Date
- 2025-11-11
- Estimated Expiration
- 2043-07-27
AI Technical Summary
Existing technologies make it difficult to prepare coatings with high light transmittance and superhydrophobic properties on glass, resulting in impaired light transmittance and safety hazards during use.
A composite structure of polyurethane layer and hydrophobic silica layer is adopted. By spraying modified silica onto polyurethane layer and pressing and curing, a transparent superhydrophobic coating is formed, ensuring the transparency and hydrophobicity of the coating.
It achieves high light transmittance and excellent hydrophobic properties, possesses self-cleaning ability, and improves the safety and transparency of the glass.
Smart Images
Figure CN116924698B_ABST
Abstract
Description
Technical Field
[0001] This invention relates to the field of hydrophobic coating materials technology, and in particular to a transparent superhydrophobic coating, its preparation method, and its application. Background Technology
[0002] Glass is one of the most widely used materials in daily life and production, a product of modern civilization. From eyeglasses and car windshields to decorative glass in large buildings, glass has greatly improved people's quality of life. However, glass comes into contact with dust and rain, which can impair its light transmittance over time and pose safety hazards. Therefore, the glass cleaning industry has developed, and while existing technology has produced superhydrophobic coatings for glass, achieving high light transmittance remains a significant challenge. Thus, developing coatings with high light transmittance and superior superhydrophobic properties is of immense value for transparent glass. Summary of the Invention
[0003] In view of this, the purpose of this invention is to provide a transparent superhydrophobic coating, its preparation method, and its application. The transparent superhydrophobic coating provided by this invention has excellent light transmittance and hydrophobicity.
[0004] To achieve the above-mentioned objectives, the present invention provides the following technical solution:
[0005] The present invention provides a transparent superhydrophobic coating, which is attached to a substrate. The transparent superhydrophobic coating includes a polyurethane layer attached to the substrate and a hydrophobic silica layer attached to the polyurethane layer.
[0006] The thickness of the hydrophobic silica layer is 300–500 nm.
[0007] Preferably, the hydrophobic silica in the hydrophobic silica layer is modifier-modified silica; the modifier includes 1H,1H,2H,2H-perfluorodecyltrimethoxysilane and / or hexadecyltrimethoxysilane.
[0008] Preferably, the thickness of the polyurethane layer is 25–30 μm.
[0009] This invention also provides a method for preparing the transparent superhydrophobic coating described in the above technical solution, comprising the following steps:
[0010] Silica, a modifier, and an alcohol solvent are mixed and modified to obtain hydrophobic silica.
[0011] Dissolve the polyurethane to obtain a polyurethane sol;
[0012] The polyurethane sol is coated onto the substrate and dried to obtain a polyurethane coating.
[0013] The hydrophobic silica is sprayed onto the polyurethane coating, and then pressed and cured sequentially to obtain the transparent superhydrophobic coating.
[0014] Preferably, the modifier includes 1H,1H,2H,2H-perfluorodecyltrimethoxysilane and / or hexadecyltrimethoxysilane; the ratio of silicon dioxide to modifier is 1g:(0.5-0.9)mL.
[0015] Preferably, the modification is performed at room temperature for 2 hours.
[0016] Preferably, the reagent used to dissolve the polyurethane is N,N-dimethylformamide; the ratio of the amount of polyurethane to the reagent used to dissolve the polyurethane is 1 g: (7-10) mL.
[0017] Preferably, the pressing pressure is 200-500 Pa and the pressing time is 10-20 min.
[0018] Preferably, the curing temperature is 120–180°C and the curing time is 2–3 hours.
[0019] The present invention also provides the application of the transparent superhydrophobic coating described in the above technical solution or the transparent superhydrophobic coating obtained by the preparation method described in the above technical solution in the field of self-cleaning.
[0020] This invention provides a transparent superhydrophobic coating, which is adhered to a substrate. The transparent superhydrophobic coating includes a polyurethane layer adhered to the substrate and a hydrophobic silica layer adhered to the polyurethane layer; the thickness of the hydrophobic silica layer is 300–500 nm. The surface of the transparent superhydrophobic coating of this invention has only a thin layer of hydrophobic silica embedded on the surface of the polyurethane layer, so that the white modified silica does not affect the transparency of the coating. The use of modified silica gives the coating superhydrophobicity, and thus self-cleaning ability.
[0021] This invention also provides a method for preparing the transparent superhydrophobic coating described above, comprising the following steps: mixing silica, a modifier, and an alcohol solvent, and modifying the mixture to obtain hydrophobic silica; dissolving polyurethane to obtain a polyurethane sol; coating the polyurethane sol onto a substrate and drying it to obtain a polyurethane coating; spraying the hydrophobic silica onto the polyurethane coating, and then pressing and curing the mixture sequentially to obtain the transparent superhydrophobic coating. The preparation method provided by this invention is simple to operate and easy to industrialize.
[0022] Furthermore, compared to slow curing at room temperature, the curing temperature is controlled at 120–180°C to further improve the permeability of polyurethane. Attached Figure Description
[0023] Figure 1 The following are test results of the transparent superhydrophobic coating obtained in Example 1: (a) is the contact angle test result of the obtained transparent superhydrophobic coating, (b) is the roll-off angle test result of the obtained transparent superhydrophobic coating, and (c) is the anti-adhesion test result of the obtained transparent superhydrophobic coating.
[0024] Figure 2 Photographs of water droplets stained with blue ink dropped onto the surfaces of ordinary glass substrates ((a1) and (b1)) and transparent superhydrophobic coatings ((a2) and (b2)), where (a1) and (a2) are front views and (b1) and (b2) are top views;
[0025] Figure 3 The image shows the UV-Vis transmittance of the transparent superhydrophobic coating obtained in Example 1.
[0026] Figure 4 The image shows the self-cleaning performance of the transparent superhydrophobic coating obtained in Example 1. Detailed Implementation
[0027] The present invention provides a transparent superhydrophobic coating, wherein the transparent superhydrophobic coating is attached to a substrate, and the transparent superhydrophobic coating includes a polyurethane layer attached to the substrate and a hydrophobic silica layer attached to the polyurethane layer.
[0028] The thickness of the hydrophobic silica layer is 300–500 nm.
[0029] In this invention, the substrate is preferably made of glass, ceramic, steel or alloy.
[0030] The transparent superhydrophobic coating provided by the present invention includes a polyurethane layer attached to the substrate, wherein the thickness of the polyurethane layer is preferably 25-30 μm.
[0031] The transparent superhydrophobic coating provided by this invention includes a hydrophobic silica layer attached to the polyurethane layer. In this invention, the hydrophobic silica in the hydrophobic silica layer is preferably modified silica; the modifying agent preferably includes 1H,1H,2H,2H-perfluorodecyltrimethoxysilane and / or hexadecyltrimethoxysilane, more preferably 1H,1H,2H,2H-perfluorodecyltrimethoxysilane. In this invention, the thickness of the hydrophobic silica layer is 300–500 nm, preferably 300 nm.
[0032] This invention also provides a method for preparing the transparent superhydrophobic coating described in the above technical solution, comprising the following steps:
[0033] Silica, a modifier, and an alcohol solvent are mixed and modified to obtain hydrophobic silica.
[0034] Dissolve the polyurethane to obtain a polyurethane sol;
[0035] The polyurethane sol is coated onto the substrate and dried to obtain a polyurethane coating.
[0036] The hydrophobic silica is sprayed onto the polyurethane coating, and then pressed and cured sequentially to obtain the transparent superhydrophobic coating.
[0037] Unless otherwise specified, all raw materials used in this invention are preferably commercially available products.
[0038] This invention involves mixing silica, a modifier, and an alcohol solvent to modify the silica, thereby obtaining hydrophobic silica.
[0039] In this invention, the particle size of the silica is preferably 30–80 nm. In this invention, the modifier preferably includes 1H,1H,2H,2H-perfluorodecyltrimethoxysilane (FAS) and / or hexadecyltrimethoxysilane, more preferably 1H,1H,2H,2H-perfluorodecyltrimethoxysilane. In this invention, the alcohol solvent preferably includes ethanol.
[0040] In this invention, the preferred ratio of silica to modifier is 1 g:(0.5-0.9) mL. In this invention, the preferred ratio of silica to alcohol solvent is 1 g:(30-70) mL.
[0041] In this invention, the mixing of silica, modifier, and alcohol solvent preferably includes the following steps: mixing the modifier and alcohol solvent to perform a first dispersion to obtain a modifier dispersion; and mixing the modifier dispersion with silica. In this invention, the first dispersion is preferably performed at room temperature for 2 hours.
[0042] In this invention, the modification temperature is preferably room temperature, i.e., no additional heating or cooling is required, and the time is preferably 3 hours.
[0043] After modification, the present invention preferably further includes drying the modified system; the drying equipment is preferably an oven. The present invention does not specifically limit the drying temperature and time, as long as it can be dried to a powder state.
[0044] This invention dissolves polyurethane to obtain a polyurethane sol.
[0045] In this invention, the polyurethane is preferably thermoplastic polyurethane. In this invention, the reagent used to dissolve the polyurethane is preferably N,N-dimethylformamide. In this invention, the preferred ratio of the amount of polyurethane to the reagent used to dissolve the polyurethane is 1 g:(7-10) mL.
[0046] After obtaining the polyurethane sol, the present invention coats the polyurethane sol onto a substrate and dries it to obtain a polyurethane coating.
[0047] In this invention, the coating method preferably includes one or more of brushing, scraping, and spraying. In this invention, the coating thickness of the polyurethane sol is preferably 25–30 μm. In this invention, the drying temperature is preferably room temperature, and the drying time is preferably 1–2 hours.
[0048] After obtaining the hydrophobic silica and polyurethane coating, the present invention sprays the hydrophobic silica onto the polyurethane coating, and then presses and cures it in sequence to obtain the transparent superhydrophobic coating.
[0049] In this invention, the thickness of the hydrophobic silica coating is preferably 300–500 nm. The hydrophobic silica coating method is preferably electrostatic spraying, and the parameters of the electrostatic spraying preferably include: pressure preferably 0.60–0.85 MPa, more preferably 0.65–0.80 MPa, voltage preferably 100 kV, and current preferably 100 μA. The pressing pressure is preferably 200–500 Pa, and the time is preferably 10–20 min. Pressing allows the hydrophobic silica particles to be better embedded in the polyurethane sol. The curing temperature is preferably 120–180 °C, more preferably 140–160 °C; and the curing time is preferably 2–3 h.
[0050] The present invention also provides the application of the transparent superhydrophobic coating described in the above technical solution or the transparent superhydrophobic coating obtained by the preparation method described in the above technical solution in the field of self-cleaning.
[0051] The present invention does not impose specific limitations on the application of the transparent superhydrophobic coating; any operation known to those skilled in the art can be used.
[0052] The following detailed description of the transparent superhydrophobic coating, its preparation method, and its application provided by the present invention, with reference to specific embodiments, should not be construed as limiting the scope of protection of the present invention.
[0053] Example 1
[0054] 3.5 mL of 1H,1H,2H,2H-perfluorodecyltrimethoxysilane (FAS) was dispersed in 250 mL of ethanol and dispersed at room temperature for 2 h. Then, 5 g of silica particles with a diameter of 50 nm were added and dispersed at room temperature for 3 h. The mixture was then placed in an evaporating dish and dried in an oven at 80 °C for 10 h to obtain hydrophobic silica powder. 3 g of thermoplastic polyurethane was dissolved in 25 mL of N,N dimethylformamide to prepare a polyurethane sol. Polyurethane sol was brushed onto a transparent glass surface (the thickness of the polyurethane layer was 25μm) and left to dry at room temperature for 2 hours. After the polyurethane sol surface was semi-dry, hydrophobic silica powder (the thickness of the spraying layer was 400nm) was sprayed onto the polyurethane coating surface by electrostatic spraying (pressure was 0.80MPa, voltage was 100kV, and current was 100μA). After covering the surface with nano-silica with a 200N object and pressing it for 10 minutes, it was placed in an oven at 180℃ and heated for 2 hours to form a transparent superhydrophobic coating.
[0055] The resulting transparent superhydrophobic coating has a contact angle of 156°, a roll-off angle of 1.8°, and a light transmittance of 97%.
[0056] Comparative Example 1
[0057] 3.5 mL of 1H,1H,2H,2H-perfluorodecyltrimethoxysilane (FAS) was dispersed in 250 mL of ethanol and dispersed at room temperature for 2 h. Then, 5 g of silica particles with a diameter of 50 nm were added and dispersed at room temperature for 3 h. The mixture was then placed in an evaporating dish and dried in an oven at 80 °C for 10 h to obtain hydrophobic silica powder. 3 g of thermoplastic polyurethane was dissolved in 25 mL of N,N dimethylformamide to prepare a polyurethane sol. The polyurethane sol was brushed onto a transparent glass surface (polyurethane layer thickness 25 μm). Hydrophobic silica powder (spray thickness 400 nm) was then sprayed directly onto the polyurethane surface via electrostatic spraying (pressure 0.80 MPa, voltage 100 kV, current 100 μA). After covering the surface with the nano-silica with a 200 N object and pressing for 10 min, the surface was placed in an oven at 180 °C and heated for 2 h to form a transparent superhydrophobic coating.
[0058] The resulting transparent superhydrophobic coating has a contact angle of 154°, a roll-off angle of 10°, and lower transparency than that of Example 1; the light transmittance is 75%.
[0059] Comparative Example 2
[0060] 3.5 mL of 1H,1H,2H,2H-perfluorodecyltrimethoxysilane (FAS) was dispersed in 250 mL of ethanol and dispersed at room temperature for 2 h. Then, 5 g of silica particles with a diameter of 50 nm were added and dispersed at room temperature for 3 h. The mixture was then placed in an evaporating dish and dried in an oven at 80 °C for 10 h to obtain hydrophobic silica powder. 3 g of thermoplastic polyurethane was dissolved in 25 mL of N,N dimethylformamide to prepare a polyurethane sol. The polyurethane sol was brushed onto a transparent glass surface (25 μm thick) and dried at room temperature for 2 h. After the polyurethane sol surface was semi-dry, hydrophobic silica powder (300 nm thick) was sprayed onto the polyurethane coating surface using a pneumatic spray gun. A 200 N object was placed over the surface coated with nano-silica and pressed for 10 min. The surface was then placed in an oven at 180 °C and heated for 2 h to form a transparent superhydrophobic coating.
[0061] The resulting transparent superhydrophobic coating has a contact angle of 152° and a roll-off angle of 5°, which is less uniform than the superhydrophobicity of different parts of the plane in Example 1; the light transmittance is 92%.
[0062] Characterization and performance testing
[0063] Figure 1 The figures shown are the test results of the transparent superhydrophobic coating obtained in Example 1 according to the GB / T30447-2013 method for measuring the contact angle of nanofilms. (a) shows the contact angle of the obtained transparent superhydrophobic coating, which is 156°. (b) shows the roll-off angle of the obtained transparent superhydrophobic coating, which is 1.8°. (c) shows the anti-adhesion test results of the obtained transparent superhydrophobic coating, which shows that the obtained transparent superhydrophobic coating has excellent superhydrophobic properties.
[0064] Figure 2 Photographs showing water droplets stained with blue ink dropped onto the surfaces of ordinary glass substrates ((a1) and (b1)) and transparent superhydrophobic coatings ((a2) and (b2)), where (a1) and (a2) are front views, and (b1) and (b2) are top views. Figure 2 It can be seen that the obtained transparent superhydrophobic coating has excellent anti-adhesion ability.
[0065] The UV-2600 UV-Vis spectrophotometer was used to test the UV-Vis transmittance of the transparent superhydrophobic coating obtained in Example 1 in the wavelength range of 300-800 nm. The results are as follows: Figure 3 As shown, Figure 3 In this context, TPU represents ordinary glass, and TPU / SiO2 refers to ordinary glass coated with the transparent superhydrophobic coating obtained in Example 1. Figure 3It can be seen that the transparent superhydrophobic coating obtained in Example 1 has a transmittance of up to 95% in the range of 400-800nm. Using a common glass substrate as a reference, this shows that the transparent superhydrophobic coating of the present invention has excellent light transmittance.
[0066] Dyed quartz sand was used to simulate pollutants. The dyed quartz sand was spread over the transparent superhydrophobic coating obtained in Example 1. A drop of water was placed on one side of the transparent superhydrophobic coating. (See photograph.) Figure 4 As shown, (a), (b), and (c) represent the beginning of water dripping, water flowing through the coating, and water flowing to the edge of the coating, respectively. Figure 4 It can be seen that the water droplets carry away the quartz sand, indicating that the transparent superhydrophobic coating has good self-cleaning ability.
[0067] Example 2
[0068] 3.5 mL of 1H,1H,2H,2H-perfluorodecyltrimethoxysilane (FAS) was dispersed in 250 mL of ethanol and dispersed at room temperature for 2 h. Then, 5 g of silica particles with a diameter of 50 nm were added and dispersed at room temperature for 3 h. The mixture was then placed in an evaporating dish and dried in an oven at 80 °C for 10 h to obtain hydrophobic silica powder. 3 g of thermoplastic polyurethane was dissolved in 25 mL of N,N dimethylformamide to prepare a polyurethane sol. Polyurethane sol was brushed onto a transparent glass surface (the thickness of the polyurethane layer was 25μm) and left to dry at room temperature for 2 hours. After the polyurethane sol surface was semi-dry, hydrophobic silica powder (the thickness of the spraying layer was 400nm) was sprayed onto the polyurethane coating surface by electrostatic spraying (pressure was 0.80MPa, voltage was 100kV, and current was 100μA). After covering the surface with nano-silica with a 500N object and pressing it for 10 minutes, it was placed in an oven at 180℃ and heated for 2 hours to form a transparent superhydrophobic coating.
[0069] The resulting transparent superhydrophobic coating has a contact angle of 157°, a roll-off angle of 1.8°, and a light transmittance of 95%.
[0070] Example 3
[0071] 3.5 mL of 1H,1H,2H,2H-perfluorodecyltrimethoxysilane (FAS) was dispersed in 250 mL of ethanol and dispersed at room temperature for 2 h. Then, 5 g of silica particles with a diameter of 50 nm were added and dispersed at room temperature for 3 h. The mixture was then placed in an evaporating dish and dried in an oven at 80 °C for 10 h to obtain hydrophobic silica powder. 3 g of thermoplastic polyurethane was dissolved in 25 mL of N,N dimethylformamide to prepare a polyurethane sol. Polyurethane sol was brushed onto a transparent glass surface (the thickness of the polyurethane layer was 25μm) and left to dry at room temperature for 2 hours. After the polyurethane sol surface was semi-dry, hydrophobic silica powder (the thickness of the spraying layer was 400nm) was sprayed onto the polyurethane coating surface by electrostatic spraying (pressure was 0.80MPa, voltage was 100kV, and current was 100μA). After covering the surface with nano-silica with a 200N object and pressing it for 10 minutes, it was placed in an oven at 120℃ and heated for 3 hours to form a transparent superhydrophobic coating.
[0072] The resulting transparent superhydrophobic coating has a contact angle of 155°, a roll-off angle of 2°, and a light transmittance of 94%.
[0073] The above description is only a preferred embodiment of the present invention. It should be noted that for those skilled in the art, several improvements and modifications can be made without departing from the principle of the present invention, and these improvements and modifications should also be considered within the scope of protection of the present invention.
Claims
1. A transparent superhydrophobic coating, wherein the transparent superhydrophobic coating is adhered to a substrate, characterized in that, The transparent superhydrophobic coating includes a polyurethane layer attached to the substrate and a hydrophobic silica layer attached to the polyurethane layer. The thickness of the hydrophobic silica layer is 300~500 nm; The thickness of the polyurethane layer is 25~30μm; The hydrophobic silica in the hydrophobic silica layer is modified silica; the modifier is 1H,1H,2H,2H-perfluorodecyltrimethoxysilane. The method for preparing the transparent superhydrophobic coating includes the following steps: Silica, a modifier, and an alcohol solvent are mixed and modified to obtain hydrophobic silica. Dissolve the polyurethane to obtain a polyurethane sol; The polyurethane sol is coated onto the substrate and dried to obtain a polyurethane coating. The hydrophobic silica is sprayed onto the polyurethane coating, and then pressed and cured sequentially to obtain the transparent superhydrophobic coating. The ratio of silica to modifier is 1g:(0.5~0.9)mL; The hydrophobic silica is sprayed by electrostatic spraying, and the parameters of the electrostatic spraying include: pressure of 0.60~0.85MPa, voltage of 100kV, and current of 100μA. The curing temperature is 160~180℃, and the time is 2~3h.
2. The method for preparing the transparent superhydrophobic coating according to claim 1, characterized in that, Includes the following steps: Silica, a modifier, and an alcohol solvent are mixed and modified to obtain hydrophobic silica. Dissolve the polyurethane to obtain a polyurethane sol; The polyurethane sol is coated onto the substrate and dried to obtain a polyurethane coating. The hydrophobic silica is sprayed onto the polyurethane coating, and then pressed and cured sequentially to obtain the transparent superhydrophobic coating. The modifier is 1H,1H,2H,2H-perfluorodecyltrimethoxysilane, and the ratio of silicon dioxide to modifier is 1g:(0.5~0.9)mL; The ratio of silica to modifier is 1g:(0.5~0.9)mL; The hydrophobic silica is sprayed by electrostatic spraying, and the parameters of the electrostatic spraying include: pressure of 0.60~0.85MPa, voltage of 100kV, and current of 100μA. The curing temperature is 160~180℃, and the time is 2~3h.
3. The preparation method according to claim 2, characterized in that, The modification was performed at room temperature for 2 hours.
4. The preparation method according to claim 2, characterized in that, The reagent used to dissolve the polyurethane is N,N-dimethylformamide; the ratio of polyurethane to N,N-dimethylformamide is 1g:(7~10)mL.
5. The preparation method according to claim 2, characterized in that, The pressing pressure is 200~500Pa, and the time is 10~20min.
6. The application of the transparent superhydrophobic coating according to claim 1 or the transparent superhydrophobic coating obtained by the preparation method according to any one of claims 2 to 5 in the field of self-cleaning.