Water-based fluorine-free super-hydrophobic coating as well as preparation method and application thereof

Abstract

The preparation method comprises the following steps: mixing long-carbon-chain alkylamine with first water, uniformly stirring at 60-80 DEG C, cooling to room temperature to obtain a solution A, mixing the solution A with a water-soluble silicon-oxygen compound, uniformly stirring at room temperature to obtain a solution B, adding the solution B into the solution A, uniformly stirring at room temperature to obtain the water-based fluorine-free super-hydrophobic coating, and uniformly stirring at room temperature to obtain the water-based fluorine-free super-hydrophobic coating. Mixing the solution B, long-chain silane and methyltrimethoxysilane, and uniformly stirring at room temperature to obtain a solution C; and mixing the diluted or undiluted solution C with a silane coupling agent, and uniformly stirring to obtain the water-based fluorine-free super-hydrophobic coating. The fluoride-free super-hydrophobic coating disclosed by the invention has relatively high safety, is fluoride-free and organic solvent-free, can be stored and used for at least 12 months, and has stable and excellent waterproof and antifouling properties.

Description

Technical Field

[0001] This invention belongs to the field of superhydrophobic coating technology, specifically relating to a water-based fluorine-free superhydrophobic coating, its preparation method, and its application. Background Technology

[0002] The new era's industrial development concepts and goals of building a resource-saving and environmentally friendly society and developing a circular economy have placed new demands and challenges on industries related to people's lives, such as clothing, food, housing, and transportation. For the clothing and textile industry, which is indispensable to daily life, developing waterproof and stain-resistant fabrics has become a top priority. This is because stain-resistant fabrics can significantly reduce the number of washes, resulting in substantial savings in daily water and electricity consumption. Furthermore, they reduce wastewater discharge into the environment, thus protecting water resources and the natural environment.

[0003] Materials with a water droplet contact angle greater than 90° are generally called hydrophobic materials. Specifically, when the water droplet contact angle is greater than 150°, the material surface is generally considered to have superhydrophobic properties. Water droplets on a lotus leaf naturally roll off, carrying away dust particles and keeping the leaf surface self-clean. Inspired by this "lotus effect," a large number of high-performance superhydrophobic materials have been developed and widely produced and applied by combining micro-roughened surface structures with low surface energy materials. In recent years, high-performance superhydrophobic materials have emerged in large numbers, and research strategies have flourished. It has been discovered that fluorocarbon compounds can significantly improve the mechanical stability and reduce the surface energy of textile surfaces, endowing fabrics with excellent hydrophobic and oleophobic properties. This discovery has attracted the attention and exploration of many researchers. Most reported superhydrophobic coatings applied to various material surfaces currently utilize fluorocarbon compounds to provide low surface energy, such as perfluorodecyltrimethoxysilane (CN 117264485A, published December 22, 2023), perfluorohexylethyltrichlorosilane (CN 115506160A, published December 23, 2022), and perfluorononane (CN 114686880A, published July 1, 2022). However, the use of these fluorocarbon compounds poses significant risks to the environment and human health, and their toxicity and harmfulness limit the production and application of superhydrophobic coatings. Therefore, many current studies use fluorine-free long-chain organosilanes (oily silanes) as the main source of low surface energy. Organic solvents are generally used to dissolve these oily silanes, such as benzoyl peroxide (CN 117511315A, published February 6, 2024) and isopropanol (CN116446182A, published July 18, 2023). These organic solvents have disadvantages such as volatility, flammability, explosiveness, and organic toxicity, posing significant safety hazards to production, transportation, and application. Therefore, current research focuses on the development of fluorine-free, safe, pollution-free, and non-toxic superhydrophobic coatings based on water-based solvents. Summary of the Invention

[0004] To address the shortcomings of existing technologies, the present invention aims to provide a method for preparing a water-based, fluorine-free, superhydrophobic coating. This method utilizes long-chain alkylamines to create an alkaline environment that catalyzes and promotes the hydrolysis and polycondensation of water-soluble silicon oxide compounds, resulting in a dispersion of long-chain alkylamine-siloxane composite nanoparticles (i.e., solution B). The long-chain ends of the long-chain alkylamine-siloxane composite nanoparticles exhibit similar compatibility with long-chain silanes. Using this dispersion, long-chain silanes are dissolved in water, and methyltrimethoxysilane is added to undergo a crosslinking polymerization reaction with the long-chain silane. This constructs a crosslinked structure formed by the polycondensation of long-chain silanes and methyltrimethoxysilane to provide low surface energy, while the long-chain alkylamine-siloxane composite nanoparticles provide a stable, wear-resistant superhydrophobic composite structure with low micro-roughness.

[0005] Another object of the present invention is to provide a water-based fluorine-free superhydrophobic coating obtained by the above preparation method.

[0006] Another object of the present invention is to provide the application of the above-mentioned waterborne fluorine-free superhydrophobic coating in textiles.

[0007] The objective of this invention is achieved through the following technical solution.

[0008] A method for preparing a water-based, fluorine-free, superhydrophobic coating includes the following steps:

[0009] Step 1: Mix long-chain alkylamine and first water, stir at 60-80°C until homogeneous, cool to room temperature to obtain solution A. Mix solution A with water-soluble silicon oxide compound, stir at room temperature until homogeneous to obtain solution B. Mix solution B, long-chain silane and methyltrimethoxysilane, stir at room temperature until homogeneous to obtain solution C. The ratio of the mass fraction of the long-chain alkylamine, the volume fraction of the water-soluble silicon oxide compound, the volume fraction of the long-chain silane and the volume fraction of methyltrimethoxysilane is (2-6):(5-15):(5-15):(7-21). The mass fraction is in g, the volume fraction is in mL, and the long-chain alkylamine has 16-19 carbon atoms.

[0010] In step 1, the long-chain alkylamine is one or a mixture of several of hexadecylamine, heptadecanylamine, octadecylamine, and nonadecanylamine.

[0011] In step 1, the water-soluble silicon oxide compound is tetraethyl orthosilicate or sodium silicate.

[0012] In step 1, the long-chain silane is hexadecyltrimethoxysilane or hexadecyltriethoxysilane.

[0013] In step 1, the ratio of the mass fraction of the long-chain alkylamine to the volume fraction of the first water is (2-6):1000, where the mass fraction is in g and the volume fraction is in mL.

[0014] In step 1, the time for mixing the long-chain alkylamine and the first water until homogeneous is 1 to 6 hours.

[0015] In step 1, solution A and water-soluble silicon oxide are mixed and stirred at room temperature for 12 to 24 hours until homogeneous to obtain solution B.

[0016] In step 1, solution B, long-chain silane, and methyltrimethoxysilane are mixed and stirred at room temperature for 4 to 24 hours until homogeneous to obtain solution C.

[0017] Step 2: Mix the diluted or undiluted C solution with the silane coupling agent and stir until homogeneous to obtain a water-based fluorine-free superhydrophobic coating. The ratio of the volume fraction of the silane coupling agent to the mass fraction of the long-chain alkylamine is (10-40):(2-6), where the mass fraction is in g and the volume fraction is in mL.

[0018] In step 2, the silane coupling agent is γ-aminopropyltriethoxysilane or γ-glycidoxypropyltrimethoxysilane.

[0019] In step 2, when the diluted C solution and the silane coupling agent are mixed: the C solution is diluted with a second water before being mixed with the silane coupling agent, wherein the dilution factor is less than or equal to 3 times.

[0020] The water-based fluorine-free superhydrophobic coating obtained by the above preparation method.

[0021] The above-mentioned water-based fluorine-free superhydrophobic coatings are used in textiles.

[0022] In the above technical solution, the water-based fluorine-free superhydrophobic coating is dipped or sprayed onto the surface of the textile and dried to form a superhydrophobic coating on the surface of the textile, thereby obtaining a hydrophobic and stain-resistant textile. The hydrophobic and stain-resistant textile has no obvious color difference, and after 1000 rubs, the surface of the hydrophobic and stain-resistant textile can still maintain superhydrophobic properties.

[0023] In the above technical solution, the surface of the hydrophobic and stain-resistant textile can still maintain superhydrophobic properties after 10 washes.

[0024] In the above technical solution, the formed superhydrophobic coating has a transmittance of more than 88% for light with wavelengths of 400–760 nm.

[0025] In the above technical solution, the textiles are chemical fiber textiles, cotton textiles, linen textiles, wool textiles, or silk textiles.

[0026] In the above technical solution, the drying temperature is 110-120℃ and the drying time is 1-2 hours.

[0027] Compared with the prior art, the beneficial effects of the present invention are as follows:

[0028] 1. The preparation method of the present invention involves uniformly dissolving long-chain silane in solution B without using organic solvents. The uniformly dissolved long-chain silane undergoes cross-linking and condensation reactions with methyltrimethoxysilane. The resulting solution C contains superhydrophobic particles composed of low surface energy substances and micro-rough structures. The long-chain silane can participate in the binding process of superhydrophobic particles to construct stable and wear-resistant superhydrophobic particles.

[0029] 2. The fluorine-free superhydrophobic coating of the present invention has high safety, and is free of fluorides and organic solvents. It can be stored and used for at least 12 months and has stable and excellent waterproof and antifouling properties.

[0030] 3. The water-based fluorine-free superhydrophobic coating of the present invention can produce hydrophobic and stain-resistant textiles that achieve superhydrophobic effects and have excellent abrasion resistance and washability.

[0031] 4. The preparation of the water-based fluorine-free superhydrophobic coating and the process of preparing hydrophobic and stain-resistant textiles of the present invention do not require special equipment, the manufacturing method is simple, the time is short, and the energy consumption during production and use is low. Attached Figure Description

[0032] Figure 1 The image shows water, milk, and red wine droplets on the surface of a hydrophobic and stain-resistant textile in Example 1.

[0033] Figure 2 The contact angle of water droplets on the surface of the hydrophobic and stain-resistant textile in Example 1 during 200 rubs;

[0034] Figure 3 The wetness of water droplets on the surface of the hydrophobic and stain-resistant textile in Example 1 after 1000 rubs;

[0035] Figure 4 This is a photograph of water, cola, and milk droplets on the surface of a hydrophobic and stain-resistant textile in Example 2;

[0036] Figure 5 The contact angle of water droplets on the surface of the hydrophobic and stain-resistant textile during 10 washes in Example 2;

[0037] Figure 6 A comparison of the light transmittance of glass slides with and without superhydrophobic coatings;

[0038] Figure 7 The surface color comparison is shown between the hydrophobic and stain-resistant textile obtained in Example 2 and the original fabric.

[0039] Figure 8 The values ​​are XPS spectra, where a is a comparison of the full spectrum of the hydrophobic and stain-resistant textile obtained in Example 2 with the original fabric, b is the Si 2p spectrum of the hydrophobic and stain-resistant textile obtained in Example 2, c is the C1 s spectrum of the original fabric, and d is the C1 s spectrum of the hydrophobic and stain-resistant textile obtained in Example 2.

[0040] Figure 9 A comparison of the Fourier transform spectra of the surfaces of the hydrophobic and stain-resistant textile obtained in Example 2 and the untreated textile fabric;

[0041] Figure 10 The contact angle of water droplets on the surface of the hydrophobic and stain-resistant textile in Example 3;

[0042] Figure 11 The contact angle of water droplets on the surface of the hydrophobic and stain-resistant textile in Example 4;

[0043] Figure 12 The contact angle of water droplets on the surface of the hydrophobic and stain-resistant textile in Example 5;

[0044] Figure 13 The water droplet contact angles of the first coated textile, the second coated textile, and the third coated textile were measured after the coating obtained in Comparative Example 1 was placed for different times and then applied to the surface of the textile.

[0045] Figure 14 The contact angle of water droplets on the surface of the first coated textile obtained in Comparative Example 1 during four washing processes;

[0046] Figure 15 b represents the appearance of the first solution. Figure 15 'a' represents the appearance of the second solution. Detailed Implementation

[0047] The technical solution of the present invention will be further described below with reference to specific embodiments.

[0048] In the following embodiments, the room temperature is 20–30°C.

[0049] The information regarding the pharmaceuticals involved in the following examples is as follows:

[0050] Octadecylamine: 90%, Shanghai Maclean Biochemical Technology Co., Ltd.;

[0051] Ethyl orthosilicate: 98%, Shanghai Maclean Biochemical Technology Co., Ltd.;

[0052] Hexadecyltrimethoxysilane: 85%, Shanghai Maclean Biochemical Technology Co., Ltd.;

[0053] Hexadecyltriethoxysilane: 85%, Shanghai Maclean Biochemical Technology Co., Ltd.;

[0054] Methyltrimethoxysilane: 98%, Shanghai Maclean Biochemical Technology Co., Ltd.;

[0055] γ-aminopropyltriethoxysilane: 99%, Shanghai Maclean Biochemical Technology Co., Ltd.;

[0056] γ-glycidyl etheroxypropyltrimethoxysilane: 97%, Shanghai Maclean Biochemical Technology Co., Ltd.;

[0057] Polyester fiber fabrics, cotton fiber fabrics, and linen fiber fabrics were purchased from Tianjin Huada Garment Co., Ltd.

[0058] In the following examples, the ethanol is a 95% industrial ethanol solution, purchased from Tianjin Jindong Tianzheng Fine Chemical Reagent Factory.

[0059] In the following examples, the unit of mass parts is g, and the unit of volume parts is mL.

[0060] Example 1

[0061] A method for preparing a water-based, fluorine-free, superhydrophobic coating includes the following steps:

[0062] Step 1: Disperse the long-chain alkylamine in first water and stir at 60°C for 4 hours until homogeneous. Cool to room temperature to obtain solution A. Mix solution A with a water-soluble silicon oxide compound and stir at room temperature for 15 hours until homogeneous to obtain solution B. Mix solution B, long-chain silane, and methyltrimethoxysilane and stir at room temperature for 8 hours until homogeneous to obtain solution C. The ratio of the volume fraction of first water, the mass fraction of long-chain alkylamine, the volume fraction of water-soluble silicon oxide compound, the volume fraction of long-chain silane, and the volume fraction of methyltrimethoxysilane is 1000:2:5:5:7. The long-chain alkylamine is octadecylamine, the long-chain silane is hexadecyltrimethoxysilane, and the water-soluble silicon oxide compound is tetraethyl orthosilicate.

[0063] Step 2: Mix solution C (undiluted) and silane coupling agent and stir until homogeneous to obtain a water-based fluorine-free superhydrophobic coating. The volume ratio of silane coupling agent to mass ratio of long-chain alkylamine is 10:2, and the silane coupling agent is γ-aminopropyltriethoxysilane.

[0064] After the water-based fluorine-free superhydrophobic coating obtained in Example 1 was left to stand at room temperature for 1 month, it was applied to the surface of a textile (the textile was cleaned with ethanol and deionized water in sequence before application). The textile was dried at 110°C for 2 hours, and a superhydrophobic coating was formed on the surface of the textile, resulting in a hydrophobic and stain-resistant textile. The textile was a polyester fiber fabric (a chemical fiber textile). The application method was as follows: the textile was immersed in the water-based fluorine-free superhydrophobic coating obtained in Example 1 for 30 minutes at room temperature.

[0065] The water droplet contact angle and water droplet roll-off angle of the hydrophobic and stain-resistant textile obtained in Example 1 were tested using a DSA100 contact angle tester. The water droplet contact angle of the hydrophobic and stain-resistant textile obtained in Example 1 was 156.6° and the water droplet roll-off angle was 2.5°, exhibiting superhydrophobic properties. When water, milk, and red wine were dropped onto the surface of the hydrophobic and stain-resistant textile obtained in Example 1, the water, milk, and red wine droplets all formed spherical shapes on the surface, exhibiting good stain-resistant properties, as shown in the photograph. Figure 1 As shown.

[0066] The hydrophobic and stain-resistant textile obtained in Example 1 was subjected to a friction test according to AATCC 118-2013 standard. The change in the water droplet contact angle on the surface of the hydrophobic and stain-resistant textile obtained in Example 1 during the friction process is as follows: Figure 2 As shown, from Figure 2 As can be seen, the surface of the hydrophobic and stain-resistant textile obtained in Example 1 still maintains its superhydrophobic properties after 200 rubs. Further rubbing experiments were conducted, and after 1000 rubs, the water droplet wetting state of the surface of the hydrophobic and stain-resistant textile obtained in Example 1 was as follows: Figure 3 As shown, from Figure 3 It can be seen that after 1000 rubs, the surface of the hydrophobic and stain-resistant textile obtained in Example 1 can still maintain superhydrophobic properties.

[0067] Example 2

[0068] A method for preparing a water-based, fluorine-free, superhydrophobic coating includes the following steps:

[0069] Step 1: Disperse the long-chain alkylamine in first water and stir at 65°C for 5 hours until homogeneous. Cool to room temperature to obtain solution A. Mix solution A with a water-soluble silicon oxide compound and stir at room temperature for 13 hours until homogeneous to obtain solution B. Mix solution B, long-chain silane, and methyltrimethoxysilane and stir at room temperature for 4 hours until homogeneous to obtain solution C. The ratio of the volume fraction of first water, the mass fraction of long-chain alkylamine, the volume fraction of water-soluble silicon oxide compound, the volume fraction of long-chain silane, and the volume fraction of methyltrimethoxysilane is 1000:4:10:10:14. The long-chain alkylamine is hexadecylamine, the long-chain silane is hexadecyltrimethoxysilane, and the water-soluble silicon oxide compound is tetraethyl orthosilicate.

[0070] Step 2: Dilute solution C with second water and mix it with silane coupling agent. Stir until homogeneous to obtain water-based fluorine-free superhydrophobic coating. The volume ratio of silane coupling agent to mass ratio of long-chain alkylamine is 10:4. The silane coupling agent is γ-aminopropyltriethoxysilane, and the dilution factor is 3 times.

[0071] After the water-based fluorine-free superhydrophobic coating obtained in Example 2 was left to stand at room temperature for 2 months, it was applied to the surface of a textile (the textile was cleaned with ethanol and deionized water in sequence before application). The coating was dried at 120°C for 2 hours, and a superhydrophobic coating was formed on the surface of the textile, resulting in a hydrophobic and stain-resistant textile. The textile was a polyester fiber fabric (a chemical fiber textile). The application method was as follows: the textile was immersed in the water-based fluorine-free superhydrophobic coating obtained in Example 2 for 30 minutes at room temperature.

[0072] The water droplet contact angle and water droplet roll-off angle of the hydrophobic and stain-resistant textile obtained in Example 2 were tested using a DSA100 contact angle tester. The water droplet contact angle of the surface of the hydrophobic and stain-resistant textile obtained in Example 2 was 155.8°, and the water droplet roll-off angle was 4.3°. When water, cola, and milk were added to the surface of the hydrophobic and stain-resistant textile obtained in Example 2, the water, cola, and milk droplets all formed spherical shapes on the surface, exhibiting good stain-resistant performance. The resulting photographs are shown below. Figure 4 As shown.

[0073] The hydrophobic and stain-resistant textile obtained in Example 2 was washed using the GB / T 8629-2017 standard. The change in the water droplet contact angle on the surface of the hydrophobic and stain-resistant textile obtained in Example 2 during the washing process is as follows: Figure 5 As shown. From Figure 5 It can be seen that the surface of the hydrophobic and stain-resistant textile obtained in Example 2 can still maintain superhydrophobic properties after 10 washes.

[0074] A transparent glass slide was immersed in the water-based fluorine-free superhydrophobic coating obtained in Example 2 at room temperature. After removal, a superhydrophobic coating was formed on the glass slide. The transmittance was measured using a UV-Vis spectrophotometer. Figure 6 As shown. The light transmittance of the glass slide with the superhydrophobic coating is as follows. Figure 6 As shown in the image of "Coated glass," the superhydrophobic coating has a transmittance of over 88% for light wavelengths of 400–760 nm. The transmittance of the glass slide before immersion in the water-based, fluorine-free superhydrophobic coating is as follows: Figure 6 As shown in the image "Bareglass".

[0075] The hydrophobic and stain-resistant textiles obtained in Example 2 ( Figure 7 The "modified fabric" in the middle is compared with the original fabric (polyester fiber fabric) that has not undergone superhydrophobic modification treatment. Figure 7 A macroscopic comparison of the surface color of the "original fabric" is performed, such as... Figure 7 As shown, there is no obvious color difference between the two. Combined with the light transmittance of the superhydrophobic coating, it can be explained that when the water-based fluorine-free superhydrophobic coating prepared in Example 2 is applied to textiles (polyester fiber fabrics), the color of the textiles themselves will not change, there will be no color difference, and the superhydrophobic coating is transparent.

[0076] The hydrophobic and stain-resistant textiles obtained in Example 2 were analyzed using X-ray photoelectron spectroscopy. Figure 8 The term "Treated fabric" in "a" refers to untreated textile fabrics (polyester fabrics). Figure 8 The chemical elements on the surface of "Untreated fabric" (a) were analyzed, such as... Figure 8 As shown. Figure 8As shown in Figure a, the spectrum of the hydrophobic and stain-resistant textile obtained in Example 2 significantly showed an increase in silicon signal compared to the measurement signal of the untreated textile fabric. Figure 8 In the b-th phase, the Si2p signal, centered at 102.4 eV, corresponds to the value of a silicon-oxygen single bond. The appearance of this signal indicates that silicon-oxygen bonds have formed on the surface of the superhydrophobic coating. Figure 8 As shown in Figure c, multiple different signal absorption peaks can be seen in the spectrum. These absorption peaks are due to the different carbon atom states in the C1s spectrum of untreated textile fabrics, such as CC / CH / CO / C=O. Figure 8 The C1s signal is stronger and symmetrically distributed in the d-coating. This is because the water-based fluorine-free superhydrophobic coating is successfully bonded to the fabric surface. The signal absorption peak of carbon on the surface of the superhydrophobic coating mainly comes from the carbon-carbon bonds and carbon-hydrogen bonds in the alkyl carbon chain skeleton. Because the superhydrophobic coating covers the fabric surface, it exceeds the detection range of XPS and cannot detect the carbon-oxygen bonds of untreated textile fabrics.

[0077] The hydrophobic and stain-resistant textiles obtained in Example 2 were analyzed using Fourier transform infrared spectroscopy. Figure 9 "Treated fabric" and untreated textile fabrics (polyester fabrics) Figure 9 The chemical functional groups on the surface of "untreated fabric" were detected. Figure 9 As shown, the hydrophobic and stain-resistant textile obtained in Example 2 and the untreated textile fabric have a cross-sectional area of ​​2923 cm⁻¹. -1 There are strong absorption peaks of the methyl group vibration in the vicinity, at 2855 cm⁻¹. -1 Strong methylene group vibrational absorption peaks are present in the vicinity. Untreated textile fabrics show absorption peaks at 3430 cm⁻¹. -1 A hydroxyl absorption peak appeared at 1635 cm⁻¹. -1 A vibrational absorption peak of the carbon-oxygen double bond appeared at 1090 cm⁻¹, while the hydroxyl absorption peak of the hydrophobic and stain-resistant textile obtained in Example 2 was significantly weakened, and the absorption peak of the carbon-oxygen double bond was significantly strengthened. This is because the water-based fluorine-free superhydrophobic coating consumed the hydroxyl groups during the bonding process with the fabric. The hydrophobic and stain-resistant textile showed a vibrational absorption peak of the carbon-oxygen double bond at 1090 cm⁻¹. -1 and 1231cm -1 A new silicon-oxygen-silicon covalent bond absorption peak appeared at 726 cm⁻¹. -1 The appearance of new silicon-carbon bond absorption peaks indicates the successful bonding of alkyl long-chain polycondensation with water-based fluorine-free superhydrophobic coatings to the fabric surface.

[0078] Examples 3-5

[0079] A method for preparing a water-based, fluorine-free, superhydrophobic coating includes the following steps:

[0080] Step 1: Disperse the long-chain alkylamine in first water, stir at A℃ for B hours until homogeneous, cool to room temperature to obtain solution A. Mix solution A with water-soluble silicon oxide compound, stir at room temperature for C hours until homogeneous to obtain solution B. Mix solution B, long-chain silane and methyltrimethoxysilane, stir at room temperature for D hours until homogeneous to obtain solution C. The ratio of the volume fraction of first water, the mass fraction of long-chain alkylamine, the volume fraction of water-soluble silicon oxide compound, the volume fraction of long-chain silane and the volume fraction of methyltrimethoxysilane is E, the long-chain alkylamine is X, the long-chain silane is Y, and the water-soluble silicon oxide compound is W.

[0081] Step 2: Mix solution C (undiluted) and silane coupling agent, and stir until homogeneous to obtain a water-based fluorine-free superhydrophobic coating. The volume ratio of the silane coupling agent to the mass ratio of the long-chain alkylamine is F, and the silane coupling agent is Z. A, B, C, D, E, F, X, Y, Z, and W are shown in Table 1.

[0082] Table 1

[0083]

[0084]

[0085] The water-based fluorine-free superhydrophobic coating obtained in Example 3 was left to stand at room temperature for 3 months before being applied to the surface of a textile (the textile was cleaned successively with 0.1 mol / L NaOH aqueous solution, ethanol, and deionized water before application). The coating was then dried at 110°C for 1 hour, forming a superhydrophobic coating on the textile surface, resulting in a hydrophobic and stain-resistant textile. The textile was a cotton fiber fabric (purchased from Tianjin Huada Garment Co., Ltd.). The application method was as follows: the textile was immersed in the water-based fluorine-free superhydrophobic coating obtained in Example 3 for 30 minutes at room temperature. A water droplet contact angle experiment was conducted on the hydrophobic and stain-resistant textile obtained in Example 3 using a DSA100 contact angle meter. The results are as follows: Figure 10 As shown. From Figure 10 As can be seen from Example 3, the surface water droplet contact angle of the hydrophobic and stain-resistant textile obtained is 153.4 degrees, which shows excellent superhydrophobic properties.

[0086] The water-based fluorine-free superhydrophobic coating obtained in Example 4 was left to stand at room temperature for 4 months before being applied to the surface of a textile (the textile was cleaned successively with 0.1 mol / L NaOH aqueous solution, ethanol, and deionized water before application). The coating was then dried at 110°C for 2 hours, resulting in a superhydrophobic coating on the textile surface, thus obtaining a hydrophobic and stain-resistant textile. The textile was a cotton fiber fabric (purchased from Tianjin Huada Garment Co., Ltd.). The application method was as follows: the textile was immersed in the water-based fluorine-free superhydrophobic coating obtained in Example 4 for 30 minutes at room temperature. A water droplet contact angle test was performed on the hydrophobic and stain-resistant textile obtained in Example 4 using a DSA100 contact angle meter. The results are as follows: Figure 11 As shown. From Figure 11 As can be seen from Example 4, the surface water droplet contact angle of the hydrophobic and stain-resistant textile obtained is 152.7 degrees, which shows good superhydrophobic properties.

[0087] The water-based fluorine-free superhydrophobic coating obtained in Example 5 was left to stand at room temperature for 8 months before being applied to the surface of a textile (the textile was cleaned sequentially with ethanol and deionized water before application). The coating was then dried at 120°C for 1 hour, resulting in a superhydrophobic coating on the textile surface, thus obtaining a hydrophobic and stain-resistant textile. The textile was a hemp fiber fabric (hemp textile, purchased from Tianjin Huada Garment Co., Ltd.). The application method was as follows: the textile was immersed in the water-based fluorine-free superhydrophobic coating obtained in Example 5 for 30 minutes at room temperature. The water droplet contact angle of the hydrophobic and stain-resistant textile obtained in Example 5 (with the water-based fluorine-free superhydrophobic coating left to stand for 8 months) was tested using a DSA100 contact angle meter. The results are as follows: Figure 12 As shown. From Figure 12 As can be seen from Example 5, the surface water droplet contact angle of the hydrophobic and stain-resistant textile obtained is 147.4 degrees, which shows good hydrophobic properties.

[0088] The water-based fluorine-free superhydrophobic coating obtained in Example 5 was left to stand at room temperature for 12 months before being applied to the surface of a textile (the textile was cleaned sequentially with ethanol and deionized water before application). The coating was then dried at 120°C for 1 hour, resulting in a superhydrophobic coating on the textile surface, thus obtaining a hydrophobic and stain-resistant textile. The textile was a hemp fiber fabric (hemp textile, purchased from Tianjin Huada Garment Co., Ltd.). The application method was as follows: the textile was immersed in the water-based fluorine-free superhydrophobic coating obtained in Example 5 for 30 minutes at room temperature. The water droplet contact angle of the hydrophobic and stain-resistant textile obtained in Example 5 (after 12 months of standing with the water-based fluorine-free superhydrophobic coating) was tested using a DSA100 contact angle meter. The surface water droplet contact angle of the hydrophobic and stain-resistant textile was 146.7 degrees, which is close to the water droplet contact angle of the hydrophobic and stain-resistant textile obtained after "8 months of standing with the water-based fluorine-free superhydrophobic coating obtained in Example 5".

[0089] Comparative Example 1

[0090] A method for preparing a coating includes the following steps:

[0091] Step 1: Disperse the long-chain alkylamine in water and stir at 60°C for 3 hours to obtain the first solution. Add the long-chain silane to the first solution, and then add methyltrimethoxysilane. Stir vigorously at 800 r / min at 60°C for 10 hours to obtain the second solution. The ratio of the volume fraction of water, the mass fraction of the long-chain alkylamine, the volume fraction of the long-chain silane, and the volume fraction of methyltrimethoxysilane is 1000:2:5:7. The long-chain alkylamine is hexadecylamine, and the long-chain silane is hexadecyltrimethoxysilane.

[0092] Step 2: Add silane coupling agent to the second solution and stir vigorously at 800 r / min for 1 h until homogeneous to obtain coating. The volume ratio of silane coupling agent to mass ratio of long-chain alkylamine is 40:2, and the silane coupling agent is γ-aminopropyltriethoxysilane.

[0093] The coating obtained in this comparative example was immediately applied to the surface of the textile (after 0 hours of storage). The application method was to immerse the textile in the coating after 0 hours of storage for 30 minutes and then dry it at 110°C for 2 hours to obtain the first coated textile.

[0094] The coating obtained in this comparative example was left to stand at room temperature for 1 day and then applied to the surface of the textile. The coating method was to soak the textile in the coating after it had been left to stand at room temperature for 1 day for 30 minutes and then dry it at 110°C for 2 hours to obtain the second coated textile.

[0095] The coating obtained in this comparative example was left to stand at room temperature for two days and then applied to the surface of the textile. The coating method was to soak the textile in the coating after it had been left to stand at room temperature for 2 days for 30 minutes and then dry it at 110°C for 2 hours to obtain the third coated textile.

[0096] The textile used in this comparative example is a polyester fiber fabric, which was cleaned sequentially with ethanol and deionized water before being dipped in the coating. The immersion temperature was room temperature.

[0097] The water droplet contact angle of the first coated textile, the second coated textile, and the third coated textile was tested using a DSA100 contact angle tester, and the results are as follows: Figure 13 As shown. From Figure 13As can be seen, the water droplet contact angle on the surface of the first coated textile is 142°, the second coated textile is 125°, and the third coated textile is 118°, exhibiting hydrophobic characteristics. However, as the storage time increases, the hydrophobic effect tends to deteriorate, and the contact angle decreases. A low contact angle means that excellent hydrophobic performance cannot be achieved. This indicates that although the surface of the coated textile obtained by Comparative Example 1 can exhibit hydrophobic properties, it needs improvement. Furthermore, the contact angle gradually decreases with time, indicating that the coating obtained by Comparative Example 1 has a short shelf life.

[0098] The first coated textile obtained in Comparative Example 1 was washed using the GB / T 8629-2017 standard. The change in the water droplet contact angle on the surface of the coated textile during the washing process is as follows: Figure 14 As shown. From Figure 14 As can be seen, the first coated textile lost its hydrophobic properties after the first wash, and became hydrophilic after two washes. The coating obtained in the comparative example has poor wash resistance, affecting practical use. Because the coating obtained in Comparative Example 1 has poor performance, there is no point in conducting friction tests.

[0099] Example 6

[0100] Water solubility test of long-chain silanes:

[0101] Test 1: A long-chain alkylamine was dispersed in water and stirred at 60°C for 4 hours until homogeneous. After cooling to room temperature, solution A was obtained. A water-soluble silicon oxide compound was added to solution A and stirred at room temperature for 12 hours until homogeneous, resulting in solution B. A long-chain silane was added to solution B and stirred at room temperature for 4 hours until homogeneous, resulting in solution 1. Solution 1 was allowed to stand at room temperature for 2 hours. [The remaining text appears to be incomplete and possibly contains errors.] Figure 15 As shown in b, the first solution showed no stratification or precipitation, indicating that the long-chain silane was effectively dispersed in water.

[0102] Test 2: Long-chain alkylamines were dispersed in water and stirred at 60°C for 4 hours until homogeneous. After cooling to room temperature, solution A was obtained. Long-chain silanes were added to solution A and stirred at room temperature for 6 hours until homogeneous, yielding solution two. Solution two was allowed to stand at room temperature for 2 hours. [The remaining text appears to be incomplete and requires further context.] Figure 15 As shown in Figure a, a clear layering phenomenon occurred in the second solution, indicating that the long-chain silane could not dissolve in water.

[0103] The comparison between Test 1 and Test 2 demonstrates that the composite water-soluble cosolvent obtained by reacting long-chain alkylamines with water-soluble silicon oxides in water achieves effective and stable dispersion of long-chain silanes in aqueous solutions.

[0104] In this embodiment, the long-chain alkylamine is octadecylamine, the long-chain silane is hexadecyltrimethoxysilane, and the water-soluble silicon oxide compound is tetraethyl orthosilicate.

[0105] The present invention has been described above by way of example. It should be noted that any simple modifications, alterations or other equivalent substitutions that can be made by those skilled in the art without creative effort without departing from the core of the present invention fall within the protection scope of the present invention.

Claims

1. A method for preparing a water-based, fluorine-free, superhydrophobic coating, characterized in that, Includes the following steps: Step 1: Mix long-chain alkylamine and first water, stir at 60-80°C until homogeneous, cool to room temperature to obtain solution A. Mix solution A with water-soluble silicon oxide compound, stir at room temperature until homogeneous to obtain solution B. Mix solution B, long-chain silane and methyltrimethoxysilane, stir at room temperature until homogeneous to obtain solution C. The ratio of the mass fraction of the long-chain alkylamine, the volume fraction of the water-soluble silicon oxide compound, the volume fraction of the long-chain silane and the volume fraction of methyltrimethoxysilane is (2-6):(5-15):(5-15):(7-21). The mass fraction is in g, the volume fraction is in mL, and the long-chain alkylamine has 16-19 carbon atoms. Step 2: Mix the diluted or undiluted C solution with the silane coupling agent and stir until homogeneous to obtain a water-based fluorine-free superhydrophobic coating. The ratio of the volume fraction of the silane coupling agent to the mass fraction of the long-chain alkylamine is (10-40):(2-6), where the mass fraction is in g and the volume fraction is in mL.

2. The preparation method according to claim 1, characterized in that, In step 1, the long-chain alkylamine is one or a mixture of several of hexadecylamine, heptadecanylamine, octadecylamine, and nonadecanylamine; in step 1, the water-soluble silicon oxide compound is tetraethyl orthosilicate or sodium silicate; in step 1, the long-chain silane is hexadecyltrimethoxysilane or hexadecyltriethoxysilane.

3. The preparation method according to claim 1, characterized in that, In step 1, the ratio of the mass fraction of the long-chain alkylamine to the volume fraction of the first water is (2-6):1000, where the mass fraction is in g and the volume fraction is in mL.

4. The preparation method according to claim 1, characterized in that, In step 2, the silane coupling agent is γ-aminopropyltriethoxysilane or γ-glycidoxypropyltrimethoxysilane.

5. The preparation method according to claim 1, characterized in that, In step 2, when the diluted C solution and the silane coupling agent are mixed: the C solution is diluted with a second water before being mixed with the silane coupling agent, wherein the dilution factor is less than or equal to 3 times.

6. The water-based fluorine-free superhydrophobic coating obtained by the preparation method described in claims 1 to 5.

7. The application of the water-based fluorine-free superhydrophobic coating as described in claim 6 in textiles.

8. The application according to claim 7, characterized in that, The water-based fluorine-free superhydrophobic coating is dipped or sprayed onto the surface of a textile and dried to form a superhydrophobic coating on the surface of the textile, thereby obtaining a hydrophobic and stain-resistant textile. The textile can be a chemical fiber textile, cotton textile, linen textile, wool textile, or silk textile.

9. The application according to claim 8, characterized in that, The hydrophobic and stain-resistant textile maintains its superhydrophobic properties even after 10 washes and 1000 rubs.

10. The application according to claim 7, characterized in that, The superhydrophobic coating has a transmittance of more than 88% for light with wavelengths of 400–760 nm.

Images