Super-flat diamond glaze ceramic tile and preparation method thereof

Abstract

The super-flat diamond glaze ceramic tile sequentially comprises a green body layer, a ground glaze layer, a pattern layer and a diamond glaze surface layer from bottom to top, and the green body layer is prepared from, by weight, 22-26 parts of kaolin, 9-12 parts of bauxite, 25-30 parts of quartz sand, 4-6 parts of bentonite, 16-20 parts of potassium feldspar, 3-6 parts of talcum powder, 3-5 parts of wollastonite, 2-3 parts of nanometer magnesium oxide and 1-2 parts of boron nitride; the content of aluminum in the green body layer is 18-22%, and the diamond glaze surface layer is formed by spraying cover glaze. By optimizing a green body formula, a glaze formula, a high-temperature slow-firing process and a polishing process and constructing a hydrophobic layer, the key indexes such as flatness, strength, wear resistance, hardness, antibacterial property and pollution resistance are remarkably superior to those of a traditional product, the glaze is more transparent and smoother, the pattern effect is more vivid, the mirror surface effect is more outstanding, and the glaze is suitable for high-requirement building decoration scenes.

Description

Technical Field

[0001] The present invention relates to the technical field of ceramic tiles, and particularly relates to a super-flat diamond glaze ceramic tile and a preparation method thereof. Background Art

[0002] As a basic building decoration material, ceramic tiles are widely used in residential, commercial and public buildings due to their durability, decorative diversity and controllable cost. From indoor floor tiles and wall tiles to outdoor square tiles, ceramic tiles not only play a functional role in covering the ground, but also become an important carrier for expressing spatial aesthetics. With the improvement of people's living standards, the requirements for decoration are getting higher and higher, and the limitations of traditional ceramic tiles are gradually emerging. In terms of flatness, the warping phenomenon of traditional ceramic tiles is relatively obvious, which affects the overall beauty and laying effect of the tiles; in terms of strength, the flexural strength and breaking strength of traditional ceramic tiles are relatively low and prone to cracking; in terms of wear resistance, the glaze hardness and wear resistance grade of traditional ceramic tiles are limited, and scratches and wear are prone to occur, reducing the decorative effect and service life; in addition, the anti-fouling performance of traditional ceramic tiles is poor, and the surface is easily adsorbed with stains and dust, increasing the difficulty and cost of cleaning and maintenance. Therefore, there is an urgent need for a super-flat diamond glaze ceramic tile with high strength, high wear resistance, excellent antibacterial property and anti-fouling property. Summary of the Invention

[0003] The purpose of the present invention is to provide a super-flat diamond glaze ceramic tile and a preparation method thereof, aiming to solve the problems of poor flatness, low strength, poor wear resistance and weak anti-fouling property of existing ceramic tiles.

[0004] To achieve the above purpose, the present invention provides the following technical solutions: A super-flat diamond glaze ceramic tile, which sequentially includes a body layer, a base glaze layer, a pattern layer and a diamond glaze surface layer from bottom to top. The body layer includes 22-26 parts by weight of kaolin, 9-12 parts by weight of bauxite, 25-30 parts by weight of quartz sand, 4-6 parts by weight of bentonite, 16-20 parts by weight of potassium feldspar, 3-6 parts by weight of talc powder, 3-5 parts by weight of wollastonite, 2-3 parts by weight of nano-magnesium oxide, and 1-2 parts by weight of boron nitride. The aluminum content in the body layer is 18-22%. The diamond glaze surface layer is formed by spraying surface glaze. The surface glaze includes 18-22 parts by weight of α-aluminum oxide, 25-30 parts by weight of quartz powder, 20-25 parts by weight of lithium feldspar, 20-24 parts by weight of frit, 5-8 parts by weight of kaolin, 1.5-3 parts by weight of nano-diamond powder, 2-4 parts by weight of nano-titanium dioxide, 1-2.5 parts by weight of nano-zinc oxide, 1-2 parts by weight of nano-silicon dioxide, 0.5-1 part by weight of nano-indium tin oxide, 0.5-1 part by weight of dispersant, 0.1-0.3 part by weight of nano-silver, and 1-3 parts by weight of silicon carbide.

[0005] Further, the dispersant is polyacrylate or zirconia.

[0006] Further, the thickness of the green body layer is 10.5 - 11.5 mm, and the thickness of the diamond glaze layer is 1 - 1.2 mm.

[0007] A preparation method of super-flat diamond glaze tiles includes the following steps: S1: Obtain the green body layer through batching, ball milling, sieving, spray granulation, aging, pressing, and drying; S2: Prepare the base glaze slurry and spray the base glaze on the green body layer to form a base glaze layer; S3: Spray and print a decorative pattern on the base glaze layer through an inkjet printer to form a pattern layer; S4: Ultrasonically disperse the nanoparticles for 20 - 30 minutes at 20 - 40 kHz; S5: Prepare the surface glaze slurry and spray the surface glaze on the pattern layer, with a glaze application amount of 1000 - 1200 g / m 2 , with a glaze layer thickness of 1 - 1.2 mm, and form a diamond glaze layer after drying; S6: Put the tiles sprayed with the surface glaze into a kiln for firing. First, raise the temperature to 750 - 850 °C at a rate of 10 - 15 °C / min, hold for 30 - 40 min, then raise the temperature to 1250 - 1350 °C at a rate of 8 - 10 °C / min, and hold for 45 - 60 min; S7: Polish the fired tiles in sequence through rough polishing, fine polishing, and mirror finishing, removing 0.05 - 0.1 mm of the glaze layer; S8: Spray a water repellent on the polished tiles, cure at 150 °C for 10 minutes, and finally obtain the super-flat diamond glaze tiles.

[0008] Further, in step S7, for rough polishing, a diamond grinding head with 400 - 800 meshes is used, the rotation speed is 800 - 1000 rpm, for fine polishing, a resin grinding disc with 1500 - 3000 meshes is used, the rotation speed is 1200 - 1500 rpm, the polishing liquid uses a nano-SiO2 suspension, and for mirror finishing, a nano-level cerium oxide polishing paste is used, with a pressure of 0.1 - 0.2 MPa.

[0009] Further, in step S8, the water repellent includes, by weight, 45 - 50 parts of absolute ethanol, 38 - 42 parts of fluorosilane coupling agent, 4 - 6 parts of nano-silica, 2 - 3 parts of epoxy-modified fluorosilicon resin, 8 - 10 parts of deionized water, and 0.2 - 0.5 parts of silane coupling agent.

[0010] Compared with the prior art, the beneficial effects of the present invention are as follows: By optimizing the green body formula, glaze formula, high-temperature slow firing process, polishing process, and constructing a hydrophobic layer, the present invention is significantly superior to traditional products in key indicators such as flatness, strength, wear resistance, hardness, antibacterial property, and stain resistance. Moreover, the glaze surface is more transparent and moist, the color pattern effect is more vivid, and the mirror effect is more outstanding, which is suitable for high-demand architectural decoration scenarios.

[0011] 1. Optimize the aluminum content in the green body layer to 18 - 22%, and introduce nano - magnesium oxide and boron nitride to promote the formation of a dense and intertwined acicular mullite network structure, significantly improving the flexural strength and toughness of the green body, achieving the best balance between the strength and toughness of the green body, and effectively preventing crack generation.

[0012] 2. Adopt a nano - diamond glaze formula to form a molecular structure similar to C60 diamond, significantly enhancing the hardness and wear resistance of the glaze surface. At the same time, combined with high - temperature slow firing, increased glaze application amount and multi - stage polishing process, enhance the anti - wear ability of the glaze surface, achieve a comprehensive improvement in the flatness and texture of the glaze surface, and the brick surface reaches an ultra - flat mirror effect, solving the water ripple problem of ordinary ceramic tiles.

[0013] 3. Through the synergistic effect of a fluorosilane hydrophobic coating and a nano - silver antibacterial agent, achieve a super - hydrophobic surface with a contact angle > 150° and an antibacterial rate of 99.9%, significantly reducing the cleaning frequency. Detailed implementation mode

[0014] In order to make the technical problems, technical solutions and beneficial effects solved by the present invention more clear and understandable, the present invention will be further described in detail below in conjunction with embodiments. It should be understood that the specific embodiments described herein are only used to explain the present invention and are not used to limit the present invention. Embodiment

[0015] A kind of ultra - flat diamond glaze ceramic tile, which successively includes a green body layer, a base glaze layer, a pattern layer and a diamond glaze surface layer from bottom to top. The green body layer includes, by weight, 22 - 26 parts of kaolin, 9 - 12 parts of bauxite, 25 - 30 parts of quartz sand, 4 - 6 parts of bentonite, 16 - 20 parts of potassium feldspar, 3 - 6 parts of talc powder, 3 - 5 parts of wollastonite, 2 - 3 parts of nano - magnesium oxide, and 1 - 2 parts of boron nitride. The aluminum content in the green body layer is 18 - 22%. The diamond glaze surface layer is formed by spraying the surface glaze. The surface glaze includes, by weight, 18 - 22 parts of α - alumina, 25 - 30 parts of quartz powder, 20 - 25 parts of lithium feldspar, 20 - 24 parts of frit, 5 - 8 parts of kaolin, 1.5 - 3 parts of nano - diamond powder, 2 - 4 parts of nano - titanium dioxide, 1 - 2.5 parts of nano - zinc oxide, 1 - 2 parts of nano - silicon dioxide, 0.5 - 1 part of indium tin oxide, 0.5 - 1 part of dispersant, 0.1 - 0.3 part of nano - silver, and 1 - 3 parts of silicon carbide.

[0016] When the aluminum content in the ceramic green body is between 18% and 22%, a large number of long mullite fibers with a high aspect ratio will form in the ceramic green body, forming a dense and intertwined needle-like mullite network structure. This network structure can effectively disperse stress, significantly improve the toughness and flexural strength of the green body, and effectively prevent the generation of cracks. Research shows that when the aluminum content is less than 18%, the generation amount of mullite is insufficient and the strength of the green body decreases. When it exceeds 22%, it may lead to too much liquid phase and grain coarsening, which will instead reduce the toughness.

[0017] In this embodiment, the green body layer includes 24 parts of kaolin, 10 parts of bauxite, 28 parts of quartz sand, 4 parts of bentonite, 18 parts of potassium feldspar, 5 parts of talc powder, 4 parts of wollastonite, 3 parts of nano-magnesium oxide, and 2 parts of boron nitride by weight. The aluminum content in the green body layer is 19.5%, which significantly improves the flexural toughness of the green body and achieves the best balance between the strength and toughness of the green body. The surface glaze includes 20 parts of α-aluminum oxide, 26 parts of quartz powder, 22 parts of lithium feldspar, 20 parts of frit, 6 parts of kaolin, 2 parts of nano-diamond powder, 2 parts of nano-titanium dioxide, 1 part of nano-zinc oxide, 1 part of nano-silicon dioxide, 0.5 part of indium tin oxide, 0.5 part of dispersant, 0.2 part of nano-silver, and 2 parts of silicon carbide by weight.

[0018] Kaolin provides Al2O3 and SiO2 for the green body, forms the green body skeleton, endows plasticity, and ensures the forming stability of the green body. During the sintering process, kaolin can react with other components to form minerals such as mullite, improving the strength and toughness of the green body; Bauxite is one of the main raw materials of the ceramic green body, provides Al2O3, reacts with SiO2 to form mullite, forms a three-dimensional network structure, improves the strength and toughness of the green body, and inhibits the cracking of the green body; The main component of quartz sand is SiO2, which has a high hardness, participates in the formation of mullite, and can improve the hardness, wear resistance, and thermal stability of the green body; Bentonite, as a binder, has good plasticity, can improve the plasticity, toughness of the green body, adsorb free water to prevent drying cracks, reduce forming defects, and improve the forming performance of the green body; Potassium feldspar, as a flux, promotes the formation of the glass phase and improves the density of the green body; Talc powder introduces MgO, helps melting and reduces the thermal expansion coefficient, improves the sintering performance of the green body, and at the same time generates cordierite (2MgO·2Al2O3·5SiO2), improving the thermal shock resistance of the green body. Talc powder can also improve the whiteness of the green body and make the surface of the ceramic tile more beautiful; Wollastonite provides CaO, promotes the generation of the liquid phase, optimizes the sintering structure, reduces shrinkage deformation, and can form needle-like or fibrous crystals during the sintering process, improving the strength and toughness of the green body; Nano-magnesium oxide, as a mineralizer, accelerates the crystallization of mullite, refines the grains, and enhances the mechanical properties of the green body; Boron nitride improves the grain boundary bonding force, inhibits crack propagation, and improves toughness and thermal shock resistance.

[0019] α-aluminum oxide forms the core support framework of the diamond glaze layer, improving the hardness and high wear resistance of the glaze surface. The uniformly distributed nano-scale particles can effectively resist daily scratches, enhance the scratch resistance performance, and extend the service life of the ceramic tile; quartz powder forms SiO2 glass phase through high-temperature melting, forms a eutectic structure with α-aluminum oxide, improves the thermal stability, increases the hardness and gloss of the glaze surface, and at the same time improves the transparency of the glaze layer; potassium feldspar introduces lithium ions to optimize the surface tension of the glaze, enhances the denseness of the glaze layer, reduces the pinhole rate of the glaze surface, and improves the flatness and gloss of the glaze surface; the frit contains components such as B2O3 and Na2O, pre-synthesized amorphous vitreous body, stabilizes the chemical composition of the glaze, adjusts the fluidity and sintering range of the glaze, provides good melting performance and the uniformity of the glaze layer; kaolin improves the plasticity and sintering performance of the glaze, combines with alumina to enhance the adhesion of the glaze layer, and prevents drying shrinkage cracking; nano-diamond powder significantly improves the hardness and wear resistance of the glaze surface, and at the same time endows the glaze surface with a diamond-like luster; nano-titanium dioxide enhances the light transmittance of the glaze surface, makes the glaze layer more transparent, enhances the visual effect of the glaze surface, improves the three-dimensional sense of the pattern color, makes the pattern color more vivid and lifelike, and at the same time produces a photocatalytic effect under light to achieve the self-cleaning function; nano-zinc oxide constructs a ZnO quantum dot antibacterial layer, synergistically acts with nano-titanium dioxide, improves the photocatalytic efficiency, enhances the antibacterial performance and stain resistance of the glaze surface, and at the same time improves the gloss of the glaze layer; nano-silica forms a nano-scale network structure, enhances the flexural strength of the glaze surface, and at the same time improves the flatness of the glaze surface, fills the micro-pores, and enhances the denseness and stain resistance of the glaze surface; nano-indium tin oxide provides good electrical conductivity and optical transparency, enhances the antistatic performance of the glaze surface, and prevents dust adsorption; the dispersant prevents the aggregation of nano-particles, ensures the uniform dispersion of nano-components, and at the same time improves the rheological properties of the glaze, ensures the uniform distribution of the glaze layer, and the dispersant can be sodium polyacrylate or zirconia; nano-silver endows the glaze surface with antibacterial and mildew-proof functions, and at the same time improves the self-cleaning performance of the glaze surface; silicon carbide enhances the impact resistance of the glaze layer, and at the same time synergistically forms a diamond-like structure with nano-diamond powder, effectively improving the wear resistance performance.

[0020] Among them, the thickness of the body layer is 10.5 - 11.5 mm, 11 mm in this embodiment, which is thicker than the traditional diamond glaze ceramic tile, making the R angle better controlled. The thickness of the diamond glaze layer is 1 - 1.2 mm, 1.07 mm before polishing and 1.02 mm after polishing in this embodiment.

[0021] The preparation method of the super-flat diamond glaze ceramic tile includes the following steps: S1: Obtain the body layer through batching, ball milling, sieving, spray granulation, aging, pressing, and drying; S2: Prepare the base glaze slurry and spray the base glaze on the body layer to form a base glaze layer; S3: Spray-print the decorative pattern on the base glaze layer through an inkjet printer to form a pattern layer; S4: Ultrasonically disperse the nanoparticles for 20 - 30 minutes at 20 - 40 kHz to break the agglomeration of the nanoparticles using ultrasonic waves, ensuring their uniform distribution in the glaze slip and improving the glaze surface properties; S5: Prepare the surface glaze slip and spray it on the pattern layer. The glazing amount is 1000 g / m2, and the glaze layer thickness is 1.07 mm. The glazing amount is approximately 20% more than that of traditional diamond glaze tiles, making the glaze surface more transparent and moist, and the color effect more vivid. After drying, a diamond glaze layer is formed, endowing the tile with ultra - hard wear resistance, high gloss, and stain resistance; S6: Place the tile sprayed with surface glaze into the kiln for firing. First, raise the temperature to 800 °C at a rate of 10 - 15 °C / min and hold for 30 - 40 min, then raise the temperature to 1250 °C at a rate of 8 - 10 °C / min and hold for 60 min to ensure that the glaze material melts sufficiently and binds tightly with the body; S7: Polish the fired tile successively by rough polishing, fine polishing, and mirror finishing, removing 0.05 - 0.1 mm of the glaze layer. Due to the increase in glazing amount and mirror finishing, the mirror effect on the tile surface is more prominent, greatly reducing the generation of water ripples; S8: Spray a water - repellent agent on the polished tile and cure it at 150 °C for 10 minutes. Finally, obtain an ultra - flat diamond glaze tile. By spraying the water - repellent agent, a lotus - effect water - repellent layer is constructed to improve the stain - resistance performance.

[0022] In step S7, for rough polishing, use a diamond grinding head with 400 - 800 mesh, rotate at 800 - 1000 rpm to remove the glaze surface protrusions and firing defects; for fine polishing, use a resin grinding disc with 1500 - 3000 mesh, rotate at 1200 - 1500 rpm, and use a nano - SiO2 suspension as the polishing liquid to refine the surface to a matte or semi - matte effect; for mirror finishing, use a nano - cerium oxide polishing paste with a pressure of 0.1 - 0.2 MPa to achieve a mirror gloss.

[0023] In step S8, the water - repellent agent includes 45 - 50 parts by weight of absolute ethanol, 38 - 42 parts of fluorosilane coupling agent, 4 - 6 parts of nano - silica, 2 - 3 parts of epoxy - modified fluorosilane resin, 8 - 10 parts of deionized water, and 0.2 - 0.5 parts of silane coupling agent. The fluorosilane coupling agent forms a low - surface - energy coating with nano - SiO2, endowing the tile with hydrophobic and stain - resistant properties.

[0024] Absolute ethanol is used as a solvent; the fluorosilane coupling agent is used as the main water - repellent agent, which combines with the glaze surface through Si - O bonds to form a low - surface - energy film layer; nano - silica constructs a micro - nano rough structure to increase the contact angle to super - hydrophobic (> 150°), the epoxy - modified fluorosilane resin enhances the mechanical strength of the coating and improves the scrub resistance; deionized water promotes the hydrolysis of the fluorosilane; the silane coupling agent assists in dispersing nano - silica and improves the interfacial bonding force. Example

[0025] The difference from Example 1 is that the green body layer includes 26 parts by weight of kaolin, 9 parts of bauxite, 30 parts of quartz sand, 5 parts of bentonite, 20 parts of potassium feldspar, 3 parts of talc powder, 4 parts of wollastonite, 2 parts of nano-magnesium oxide, and 2 parts of boron nitride. The aluminum content in the green body layer is 20.4%. When spraying the surface glaze, the glaze application amount is 1050 g / m2, the glaze layer thickness is 1.13 mm, the firing temperature is 1300 °C, and after polishing, the glaze layer thickness is 1.08 mm.

[0026] Comparative example: The green body layer of traditional tiles includes, by weight: 30 parts of kaolin, 25 parts of quartz sand, 8 parts of bentonite, 25 parts of potassium feldspar, 5 parts of talc powder, and 3 parts of wollastonite. The aluminum content in the green body layer is 17.1%. The surface glaze includes, by weight: 20 parts of alumina, 26 parts of quartz powder, 22 parts of lithium feldspar, 20 parts of frit, 10 parts of kaolin, 4 parts of zinc oxide, and 5 parts of wollastonite. Its preparation method includes the following steps: S1: Obtain the green body layer through batching, ball milling, sieving, spray granulation, aging, pressing, and drying; S2: Prepare the bottom glaze slurry and spray the bottom glaze on the green body layer to form a bottom glaze layer; S3: Spray and print a decorative pattern on the bottom glaze layer through an inkjet printer to form a pattern layer; S4: Prepare the surface glaze slurry and spray the surface glaze on the pattern layer, with a glaze application amount of 850 g / m2; S5: Put the tiles sprayed with the surface glaze into a kiln and fire at 1150 °C for 60 min; S6: Polish the fired tiles. After polishing, the glaze layer thickness is 0.86 mm to obtain the tiles.

[0027] The test results of the tiles prepared in Example 1, Example 2, and the comparative example are shown in Table 1: Table 1: Comparison of test results

[0028] It can be analyzed from the above table that through optimizing the green body formula (such as aluminum content), glaze surface formula (nano materials, antibacterial components, etc.), high-temperature slow firing process, polishing process, and constructing a hydrophobic layer, Example 1 and Example 2 are significantly superior to traditional products in key indicators such as flatness, strength, wear resistance, hardness, antibacterial property, and stain resistance. Moreover, the glaze surface is more transparent and moist, the color and pattern effect is more vivid, and the mirror effect is more outstanding, which is suitable for high-demand architectural decoration scenarios.

[0029] Although the embodiments of the present invention have been shown and described, for those of ordinary skill in the art, it can be understood that various changes, modifications, substitutions, and variations can be made to these embodiments without departing from the principles and spirits of the present invention. The scope of the present invention is defined by the appended claims and their equivalents.

Claims

1. An ultra-flat diamond glaze tile, characterized in that: The invention comprises a body layer, a base glaze layer, a pattern layer and a diamond glaze layer from bottom to top. The body layer comprises 22-26 parts of kaolin, 9-12 parts of bauxite, 25-30 parts of quartz sand, 4-6 parts of bentonite, 16-20 parts of potassium feldspar, 3-6 parts of talc, 3-5 parts of wollastonite, 2-3 parts of nano magnesium oxide and 1-2 parts of boron nitride in parts by weight. The aluminum content in the body layer is 18-22%. The diamond glaze layer is formed by spraying the top glaze. The glaze comprises, by weight, 18-22 parts of α-alumina, 25-30 parts of quartz powder, 20-25 parts of lithium feldspar, 20-24 parts of frit, 5-8 parts of kaolin, 1.5-3 parts of nano diamond powder, 2-4 parts of nano titanium dioxide, 1-2.5 parts of nano zinc oxide, 1-2 parts of nano silicon dioxide, 0.5-1 parts of nano indium tin oxide, 0.5-1 parts of dispersant, 0.1-0.3 parts of nano silver, and 1-3 parts of silicon carbide.

2. The ultra-flat diamond glaze ceramic tile according to claim 1, characterized in that: The dispersant is sodium polyacrylate or zirconium oxide.

3. The ultra-flat diamond glaze ceramic tile according to claim 1, characterized in that: The green body layer has a thickness of 10.5-11.5 mm, and the diamond glaze layer has a thickness of 1-1.2 mm.

4. A method for preparing the ultra-flat diamond glaze ceramic tile according to any one of claims 1 to 3, characterized in that: The following steps are involved: S1: obtaining a green body layer by batching, ball milling, sieving, spray granulation, aging, pressing and drying; S2: preparing a base glaze slurry and spraying the base glaze on the body layer to form a base glaze layer; S3: Printing a decorative pattern on the base glaze layer by an inkjet printer to form a pattern layer; S4: nanoparticles were pre-ultrasonicated for 20-30 min, 20-40 kHz; S5: Prepare the glaze slurry and spray the glaze on the pattern layer, with a glaze amount of 1000-1200g / m 2 The thickness of the glaze layer is 1-1.2mm, and after drying, a diamond glaze layer is formed; S6: Place the glazed tiles into the kiln for firing. First, heat them up to 750-850℃ at a rate of 10-15℃ / min, keep them warm for 30-40min, then heat them up to 1250-1350℃ at a rate of 8-10℃ / min, keep them warm for 45-60min. S7: Polish the fired tiles in sequence through rough polishing, fine polishing and mirror treatment, and remove 0.05-0.1mm of the glaze layer; S8: Spray a hydrophobic agent on the polished tiles, and cure at 150° C. for 10 minutes to finally obtain ultra-flat diamond glaze tiles.

5. The method for preparing the ultra-flat diamond glaze ceramic tile according to claim 4, characterized in that: In step S7, a 400-800 mesh diamond grinding head is used for rough polishing at a rotation speed of 800-1000 rpm, a 1500-3000 mesh resin grinding disc is used for fine polishing at a rotation speed of 1200-1500 rpm, a nano-SiO2 suspension is used as the polishing liquid, and a nano-cerium oxide polishing paste is used for mirror treatment at a pressure of 0.1-0.2 MPa.

6. The method for preparing the ultra-flat diamond glaze ceramic tile according to claim 4, characterized in that: In step S8, the hydrophobic agent includes, by weight, 45-50 parts of anhydrous ethanol, 38-42 parts of fluorosilane coupling agent, 4-6 parts of nano-silicon dioxide, 2-3 parts of epoxy-modified fluorosilicone resin, 8-10 parts of deionized water, and 0.2-0.5 parts of silane coupling agent.

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