Super-hydrophobic glass repair coating and preparation process thereof

Abstract

The invention discloses a super-hydrophobic glass repair coating and a preparation process thereof, and relates to the technical field of super-hydrophobic coatings. The preparation method specifically comprises the following steps: (1) adding tetraethyl orthosilicate, ammonia water and deionized water into absolute ethyl alcohol, hydrolyzing and aging to obtain N sol; (2) dispersing hydrophobic nano silicon dioxide in absolute ethyl alcohol to obtain S sol; (3) mixing the S sol and the N sol according to a volume ratio of 7: 3 to obtain SN73 sol; (4) adding 1-3% of resin into the SN73 sol, and uniformly mixing to obtain repair sol; and (5) smearing the repair sol on the worn glass, and curing to obtain a finished product containing the super-hydrophobic glass repair coating. Tests show that the prepared coating can be used for repairing worn glass, has better light transmittance and super-hydrophobic effect, and has certain wear resistance, chemical resistance, better hardness and adhesive force.

Description

Technical Field

[0001] The present invention relates to the technical field of superhydrophobic coating, and specifically to a superhydrophobic glass repair coating and its preparation process. Background Art

[0002] There are a large number of hydroxyl groups on the surface of silicate glass, which is a hydrophilic high-energy surface. Water or liquids with lower surface tension are wet on its surface. When the glass surface encounters water or liquids with lower surface tension, a liquid film will be formed, causing the glass to lose transparency, which brings a lot of inconvenience to people's lives and work. At the same time, when the glass is exposed for a long time, it is easy to adsorb dust and other stains due to electrostatic action. Due to the poor hydrophobicity of the glass, when the liquid rolls on its surface, the pollutants rolled up by the water droplets will reattach to the glass surface because of the large contact area, making it difficult to clean. And easy wear is another major drawback of silicate glass, which will lead to a decrease in light transmittance and a reduction in the conversion rate of monocrystalline silicon solar cells.

[0003] A superhydrophobic coating is a coating with special surface wetting properties. Its contact angle with water is greater than 150°, and the difference between the advancing contact angle and the receding contact angle of the surface is less than 5º. It has potential application value in many fields and broad application prospects. However, in the existing technology, the prepared superhydrophobic coatings often have problems such as low light transmittance, general wear resistance and hardness, so they need to be solved.

[0004] In summary, to solve the above problems, it is of great significance to provide a preparation process for a superhydrophobic glass repair coating with high light transmittance, good wear resistance and high hardness. Summary of the Invention

[0005] The purpose of the present invention is to provide a superhydrophobic glass repair coating and its preparation process to solve the problems raised in the existing technology.

[0006] To achieve the above purpose, the present invention provides the following technical solutions: A preparation process for a superhydrophobic glass repair coating, comprising the following steps: Step 1: Preparation of the repair sol: S1-1: (1) Tetraethyl orthosilicate is dispersed in absolute ethanol and magnetically stirred for 25 - 30 min to obtain solution A; (2) Ammonia water, deionized water and absolute ethanol are mixed and magnetically stirred at room temperature for 25 - 30 min to obtain solution B; (3) Solution B is added dropwise to solution A, and magnetically stirred at room temperature for 2 - 3 h; The obtained solution is continuously aged at room temperature for 3 days to obtain N sol; S1-2: Hydrophobic nano-silica is dispersed in absolute ethanol to obtain S sol; S1-3: S sol and N sol are mixed and stirred evenly to obtain SN sol; This is used as the repair sol; Step 2: Preparation of superhydrophobic glass repair coating: Wash the worn glass, coat the repair sol on its surface, and dry it by ultraviolet curing to obtain a finished product with a superhydrophobic glass repair coating.

[0007] More preferably, in step S1-1: Solution A includes tetraethyl orthosilicate and absolute ethanol with a volume ratio of 7:33 - 34; Solution B includes ammonia water, deionized water and absolute ethanol with a volume ratio of 1:1.1 - 1.2:33.5 - 34; The S sol includes hydrophobic nano-silica and absolute ethanol with a mass ratio of 1 - 2:100.

[0008] More preferably, in step S1-3: The SN series sol includes S sol and N sol with a volume ratio of 7:3.

[0009] More preferably, the preparation method of the hydrophobic nano-silica includes the following steps: (1) Add nano-silica and deionized water to absolute ethanol, ultrasonically disperse evenly, add 3-aminopropyltriethoxysilane, heat and stir at 50 - 60 °C for 2 - 4 h, centrifuge, wash, and dry to obtain amino-functionalized nano-silica; (2) Add the amino-functionalized nano-silica to absolute ethanol, ultrasonically disperse evenly, add oleic acid and activator, heat and stir at 50 - 60 °C for 3 - 4 h, centrifuge, wash, and dry to obtain oleic acid-modified nano-silica; (3) Add the oleic acid-modified nano-silica to absolute ethanol, ultrasonically disperse evenly, add hexamethyldisilazane, and stir at 50 - 60 °C for 2.5 - 3.5 h to obtain hydrophobic nano-silica.

[0010] Among them, the hydrophobic nano-silica includes the following raw materials: The amino-functionalized nano-silica includes the following raw materials by mass: 1 - 2 parts of nano-silica, 10 - 20 parts of deionized water, 30 - 40 parts of absolute ethanol, 0.3 - 0.5 part of 3-aminopropyltriethoxysilane; The oleic acid-modified nano-silica includes the following raw materials by mass: 1 - 2 parts of amino-functionalized nano-silica, 30 - 40 parts of absolute ethanol, 0.45 - 0.55 part of oleic acid, 0.5 - 0.6 part of activator; The hydrophobic nano-silica includes the following raw materials by mass: 1 - 2 parts of oleic acid-modified nano-silica, 30 - 40 parts of absolute ethanol, 0.12 - 0.14 part of hexamethyldisilazane.

[0011] More preferably, in step S1-3: Mix and stir the S sol and N sol evenly to obtain the SN sol; add resin and stir evenly to obtain the mixed sol; use it as the repair sol.

[0012] More preferably, the addition amount of the resin is 1 - 3 wt% of the SN sol.

[0013] More preferably, the preparation method of the resin comprises the following steps: (1) After removing water from polytetrahydrofuran ether glycol at 140 °C and keeping it at 50 °C, 2-4 wt% concentrated phosphoric acid is added to obtain a monomer mixture; (2) Toluene-2,4-diisocyanate and dibutyltin dilaurate are mixed evenly, and the monomer mixture is slowly added dropwise, and the mixture is stirred and reacted at 50-55 °C for 3-4 h to obtain polyurethane; (3) The polyurethane, 1,4-butanediol, and pentaerythritol are mixed evenly, and the mixture is stirred and chain-extended at 55-65 °C for 2-3 h. Hydroxyethyl acrylate and p-tert-butylcatechol are added, and the mixture is subjected to end-capping reaction at 60-70 °C for 2-3 h to obtain a polyurethane prepolymer; (4) 5,5-Bis(propyl-2-ylthio)pentane-1,2,3-triol, thiourea, and 1 mol / L hydrochloric acid are mixed evenly, and the mixture is heated and stirred at 90-100 °C for 1-1.5 h, cooled to 50-60 °C, and the pH is adjusted to 7.5-8.5 under a nitrogen atmosphere, stirred for 1-1.5 h, allowed to stand for layering, and the lower organic phase is taken and purified by distillation to obtain a crosslinking agent; (5) The polyurethane prepolymer, 2-hydroxyethyl methacrylate, isobornyl acrylate, crosslinking agent, and photoinitiator are mixed evenly to obtain the resin.

[0014] Among them, the polyurethane comprises the following raw materials in parts by mass: 4-4.5 parts of toluene-2,4-diisocyanate, 19.5-20.5 parts of monomer mixture, and 0.1-0.3 parts of dibutyltin dilaurate; the polyurethane prepolymer comprises the following raw materials in parts by mass: 24-25 parts of polyurethane, 0.2-0.3 parts of 1,4-butanediol, 0.4-0.5 parts of pentaerythritol, 2.8-3 parts of hydroxyethyl acrylate, and 0.04-0.05 parts of p-tert-butylcatechol; the crosslinking agent comprises the following raw materials in parts by mass: 13-13.5 parts of 5,5-bis(propyl-2-ylthio)pentane-1,2,3-triol, 11.5-12 parts of thiourea, and 30 parts of 1 mol / L hydrochloric acid; the resin comprises a polyurethane prepolymer, 2-hydroxyethyl methacrylate, isobornyl acrylate, crosslinking agent, and photoinitiator in a mass ratio of 45-65:20-25:5-10:3-4:3.5.

[0015] More preferably, the molecular weight of polytetrahydrofuran ether glycol is 1000-1500; the activator is 1-(3-dimethylaminopropyl)-3-ethylcarbodiimide and N-hydroxysuccinimide in a mass ratio of 1:1-3; the photoinitiator is Irgacure184.

[0016] Compared with the prior art, the beneficial effects of the present application are as follows: (1) For the N sol, tetraethyl orthosilicate is used as the silicon source to hydrolyze and prepare nano-silica sol. By using specific concentrations of tetraethyl orthosilicate, amounts of ammonia water, amounts of deionized water, and reaction time, the prepared nano-silica sol particles have an average and small particle size. The prepared coating has a smooth surface and good light transmittance. The S sol is obtained by dispersing hydrophobic nano-silica in ethanol. Larger-sized silica particles are used. Since long-chain alkanes or fluoride groups are introduced in the hydrophobic nano-silica, the interaction forces between particles change, making the packing between particles tighter, with a low porosity and a high surface roughness. This results in a poor light transmittance of the prepared coating but a good hydrophobic effect. Therefore, in the present invention, SN sols with different ratios are prepared by compounding the N sol and the S sol. Through testing, the coating prepared from the sol obtained by mixing the S sol and the N sol at a volume ratio of 7:3 can maintain good light transmittance while having good hydrophobicity: the larger particles in the S sol and the uniformly smaller particles in the N sol crosslink and agglomerate together, with many nano-pores, making the porosity higher than that of the coating prepared from the S sol, increasing the light transmittance, while retaining the surface roughness and improving the hydrophobicity.

[0017] (2) The hydrophobic nano-silica of the present invention introduces amino groups through an amino-silane coupling agent and then grafts oleic acid to introduce long chains, improving the hydrophobicity of the silica and also helping to crosslink with the resin added subsequently to improve the bonding property. And using hexamethyldisilazane can further react with the unreacted silanol groups on the silica surface to further improve the hydrophobicity.

[0018] (3) The present invention also adds a small amount of resin to the sol to improve the wear resistance and hardness of the coating: The present invention uses polytetrahydrofuran ether glycol, toluene-2,4-diisocyanate, and 2-hydroxyethyl acrylate to prepare a polyurethane prepolymer with vinyl at the chain ends, which can effectively improve the hardness and wear resistance of the coating. And under the action of a photoinitiator, it can be cured by drying under ultraviolet light. The present invention introduces pentaerythritol and 1,4-butanediol as chain extenders to adjust the ratio of the hard and soft chain ends of the polyurethane segment, improving its mechanical properties and chemical resistance, and also improving the water solubility of the polyurethane, making it more uniformly dispersed in the system and improving the comprehensive wear resistance and hardness. The present invention also uses 5,5-bis(prop-2-ylthio)pentane-1,2,3-triol to prepare a polythiol as a crosslinking agent, which can react with the vinyl at the chain ends of the polyurethane and the alkenyl in the oleic acid-modified hydrophobic nano-silica to produce crosslinking, improving the wear resistance and hardness of the coating. And due to the presence of d orbitals in the outer layer of the sulfur atom, the two pairs of outermost electrons are easily polarized, making the sulfur atom have both a low molecular dispersion and a high molecular refractive index, and its molecular weight is relatively large. The prepared polythiol has a high sulfur content, making the coating have a high light transmittance. And the mercaptopropyl structure in the molecule can also reduce the surface energy and further improve the hydrophobicity.

[0019] (4)After the worn glass is treated by the coating preparation process provided by the present invention, the light transmittance has been greatly improved, so it has a repair function. Description of the Drawings

[0020] Figure 1 It is the light transmittance diagram before and after the worn glass coating is repaired with the repair sol prepared in Example 9 of the present invention.

[0021] Figure 2 In it, (a) is the light transmittance comparison diagram of Examples 2-7 of the present invention; (b) is the comparison diagram of the maximum light transmittance and water contact angle of Examples 3-7 of the present invention; (c) and (d) are the comparison diagrams of the light transmittance and reflectivity of Examples 1-3 of the present invention; Figure 3 In it, (a), (b), (c), (d) are the water contact angle test diagrams of the blank slide, Example 1, Example 2, and Example 3 of the present invention respectively; (e) and (f) are the self-cleaning effect comparison diagrams of the blank slide and Example 3 of the present invention respectively; Figure 4 In it, (a), (b), (c) are the AFM morphology diagrams of Example 1, Example 2, and Example 3 respectively, and (d), (e), (f) are the AFM 3D morphology diagrams of Example 1, Example 2, and Example 3 respectively; Figure 5 In it, (a), (b) are the SEM morphology diagrams of Example 1 of the present invention; (c), (d) are the SEM morphology diagrams of Example 2 of the present invention; (e), (f) are the SEM morphology diagrams of Example 3 of the present invention respectively; Figure 6 In it, (a), (b) are the microscopic pictures of the HB and B pencil hardness tests of Example 3 of the present invention respectively; (c) is the microscopic picture of the adhesion test of Example 3 of the present invention; (d) is the diagram of the change in light transmittance after the water droplet impact test of Example 3 of the present invention; (e) is the diagram of the change in light transmittance before and after Example 3 of the present invention is soaked in acid for 2 h and 6 h; (f) is the diagram of the change in light transmittance after Example 3 of the present invention is pasted with tape 5 times; Figure 7 It is the light transmittance diagram before and after the worn glass coating is repaired with the repair sol prepared in Example 3 of the present invention; Figure 8 It is the I-V curve diagram before and after the single-crystalline silicon solar cell coating is coated with the repair sol prepared in Example 3 of the present invention; Figure 9 It is the light transmittance comparison diagram of Example 3 of the present invention and Examples 8-10 with different resin addition ratios; Figure 10Among them, (a), (b), and (c) are the water contact angle diagrams of Examples 8, 9, and 10 of the present invention respectively; Figure 11 Among them, (a) is the diagram of the change in light transmittance after the water droplet impact test of Example 9 of the present invention; (b) is the diagram of the change in light transmittance before and after the acid treatment for 4 h and 24 h of Example 9 of the present invention; (c) is the diagram of the change in light transmittance before and after the alkali treatment for 4 h and 24 h of Example 9 of the present invention; (d) is the water contact angle test diagram after the water droplet impact test of Example 9 of the present invention; (e) is the water contact angle test diagram after the acid treatment for 24 h of Example 9 of the present invention; (f) is the water contact angle test diagram after the alkali treatment for 24 h of Example 9 of the present invention; Figure 12 Among them, (a) is the microscopic picture of the adhesion test of Example 9 of the present invention; (b) and (c) are the microscopic pictures of the 3H and 2H pencil hardness tests of Example 9 of the present invention respectively; Figure 13 Among them, (a) is the diagram of the change in water contact angle before and after the abrasion resistance test for 1 to 5 times of Example 9 of the present invention; (b) is the diagram of the change in light transmittance before and after the abrasion resistance test for 1 to 5 times of Example 9 of the present invention; Detailed implementation manners

[0022] Based on the embodiments of the present invention, all other embodiments obtained by those of ordinary skill in the art without creative efforts shall fall within the protection scope of the present invention.

[0023] It should be noted that there are no special restrictions on the purchase manufacturers of all raw materials involved in the present invention. Exemplarily, they include: tetraethyl orthosilicate, CAS: 562-90-3; nano-silica, with a particle size of 140 - 160 nm; polytetrahydrofuran ether diol, CAS: 25190-06-1; toluene-2,4-diisocyanate, CAS: 584-84-9; 2-hydroxyethyl acrylate, CAS: 818-61-1; 5,5-bis(propyl-2-ylthio)pentane-1,2,3-triol, CAS: 6301-46-8; thiourea, CAS: 62-56-6; 2-hydroxyethyl methacrylate, CAS: 868-77-9; isobornyl acrylate, CAS: 5888-33-5; hexamethyldisilazane, CAS: 999-97-3; Irgacure 184, provided by Shanghai Kayin Chemical Co., Ltd.

[0024] In the following examples, "parts" refers to parts by mass, and all raw materials are commercially available.

[0025] Among them, the preparation method of the hydrophobic nano-silica includes the following steps: (1) Add 1.5 parts of nano-silica and 15 parts of deionized water to 35 parts of absolute ethanol, ultrasonically disperse evenly, add 0.4 part of 3-aminopropyltriethoxysilane, heat and stir at 55 °C for 3 h, centrifuge, wash, and dry to obtain aminated nano-silica; (2) Add 1.5 parts of aminated nano-silica to 35 parts of absolute ethanol, ultrasonically disperse evenly, add 0.5 part of oleic acid and 0.55 part of activator, heat and stir at 55 °C for 3.5 h, centrifuge, wash, and dry to obtain oleic acid-modified nano-silica; (3) Add 1.5 parts of oleic acid-modified nano-silica to 35 parts of absolute ethanol, ultrasonically disperse evenly, add 0.13 part of hexamethyldisilazane, stir at 55 °C for 3 h to obtain hydrophobic nano-silica.

[0026] Among them, the preparation method of the resin includes the following steps: (1) After removing water from polytetrahydrofuran ether glycol at 140 °C, keep it at 50 °C, and add 2-4 wt% of concentrated phosphoric acid to obtain a monomer mixture; (2) Mix 4.25 parts of toluene-2,4-diisocyanate and 0.2 part of dibutyltin dilaurate evenly, slowly drop 20 parts of the monomer mixture, and stir and react at 50-55 °C for 3-4 h to obtain polyurethane; (3) Mix 24.5 parts of polyurethane, 0.25 part of 1,4-butanediol, and 0.45 part of pentaerythritol evenly, stir and chain-extend at 60 °C for 2.5 h, add 2.9 parts of 2-hydroxyethyl acrylate and 0.04 part of p-tert-butylcatechol, and carry out capping reaction at 65 °C for 2.5 h to obtain a polyurethane prepolymer; (4) Mix 13.4 parts of 5,5-bis(propyl-2-ylthio)pentane-1,2,3-triol, 11.7 parts of thiourea, and 30 parts of 1 mol / L hydrochloric acid evenly, heat and stir at 95 °C for 1 h, cool down to 55 °C, adjust the pH to 8 under a nitrogen atmosphere, stir for 1 h, let it stand for layering, take the lower organic phase, distill and purify to obtain a crosslinking agent; (5) Mix the polyurethane prepolymer, 2-hydroxyethyl methacrylate, isobornyl acrylate, crosslinking agent, and photoinitiator evenly according to a mass ratio of 55:20:6:3.6:3.5 to obtain the resin.

[0027] Example 1: Step 1: Preparation of the repair sol: S1-1: (1) Disperse 7 mL of tetraethyl orthosilicate in 33.6 mL of absolute ethanol and stir magnetically for 30 min to obtain Solution A; (2) Mix 1 mL of ammonia water, 1.13 mL of deionized water and 33.6 mL of absolute ethanol, and stir magnetically at room temperature for 30 min to obtain Solution B; (3) Drop Solution B into Solution A and stir magnetically at room temperature for 3 h; Keep the obtained solution aging at room temperature for 3 days to obtain N sol; Use it as the repair sol; Step 2: Preparation of superhydrophobic glass repair coating: Wash the blank glass slide, coat the repair sol on its surface, and dry it by ultraviolet curing to obtain a finished product containing a superhydrophobic glass repair coating.

[0028] Example 2: Step 1: Preparation of repair sol: S1-1: Disperse 1 g of hydrophobic nano-silica in 100 g of absolute ethanol to obtain S sol; Use it as the repair sol; Step 2: Preparation of superhydrophobic glass repair coating: Wash the blank glass slide, coat the repair sol on its surface, and dry it by ultraviolet curing to obtain a finished product containing a superhydrophobic glass repair coating.

[0029] Example 3: Step 1: Preparation of repair sol: S1-1: (1) Disperse 7 mL of tetraethyl orthosilicate in 33.6 mL of absolute ethanol and stir magnetically for 30 min to obtain Solution A; (2) Mix 1 mL of ammonia water, 1.13 mL of deionized water and 33.6 mL of absolute ethanol, and stir magnetically at room temperature for 30 min to obtain Solution B; (3) Drop Solution B into Solution A and stir magnetically at room temperature for 3 h; Keep the obtained solution aging at room temperature for 3 days to obtain N sol; S1-2: Disperse 1 g of hydrophobic nano-silica in 100 g of absolute ethanol to obtain S sol; S1-3: Mix S sol and N sol in a volume ratio of 7:3 and stir evenly to obtain SN73 sol; Use it as the repair sol; Step 2: Preparation of superhydrophobic glass repair coating: Wash the blank glass slide, coat the repair sol on its surface, and dry it by ultraviolet curing to obtain a finished product containing a superhydrophobic glass repair coating.

[0030] Examples 4 - 7: Based on Example 3, mix S sol and N sol in volume ratios of 1:9, 3:7, 5:5, and 9:1 respectively and stir evenly to obtain SN19, SN37, SN55, and SN91 sols respectively; Use them as the repair sols; The remaining processes are the same as those in Example 3.

[0031] Example 8: S1-1: (1) Disperse 7 mL of tetraethyl orthosilicate in 33.6 mL of absolute ethanol and stir magnetically for 30 min to obtain Solution A; (2) Mix 1 mL of ammonia water, 1.13 mL of deionized water and 33.6 mL of absolute ethanol, and stir magnetically at room temperature for 30 min to obtain Solution B; (3) Drop Solution B into Solution A and stir magnetically at room temperature for 3 h; Keep the obtained solution aging at room temperature for 3 days to obtain N sol; S1-2: Disperse 1 g of hydrophobic nano-silica in 100 g of absolute ethanol to obtain S sol; S1-3: Mix S sol and N sol in a volume ratio of 7:3 and stir evenly to obtain SN73 sol; Add 1 wt% of resin to SN73 sol and stir evenly to obtain a mixed sol; Use it as the repair sol; Step 2: Preparation of superhydrophobic glass repair coating: Wash the blank glass slide, coat the repair sol on its surface, and cure and dry it under ultraviolet light to obtain a finished product containing a superhydrophobic glass repair coating.

[0032] Example 9: S1-1: (1) Disperse 7 mL of tetraethyl orthosilicate in 33.6 mL of absolute ethanol and stir magnetically for 30 min to obtain Solution A; (2) Mix 1 mL of ammonia water, 1.13 mL of deionized water and 33.6 mL of absolute ethanol, and stir magnetically at room temperature for 30 min to obtain Solution B; (3) Drop Solution B into Solution A and stir magnetically at room temperature for 3 h; Keep the obtained solution aging at room temperature for 3 days to obtain N sol; S1-2: Disperse 1 g of hydrophobic nano-silica in 100 g of absolute ethanol to obtain S sol; S1-3: Mix S sol and N sol in a volume ratio of 7:3 and stir evenly to obtain SN73 sol; Add 2 wt% of resin to SN73 sol and stir evenly to obtain a mixed sol; Use it as the repair sol; Step 2: Preparation of superhydrophobic glass repair coating: Wash the blank glass slide, coat the repair sol on its surface, and cure and dry it under ultraviolet light to obtain a finished product containing a superhydrophobic glass repair coating.

[0033] Example 10: S1-1: (1) Disperse 7 mL of tetraethyl orthosilicate in 33.6 mL of absolute ethanol and stir magnetically for 30 min to obtain Solution A; (2) Mix 1 mL of ammonia water, 1.13 mL of deionized water and 33.6 mL of absolute ethanol, and stir magnetically at room temperature for 30 min to obtain Solution B; (3) Drop Solution B into Solution A and stir magnetically at room temperature for 3 h; Keep the obtained solution aging at room temperature for 3 days to obtain N sol; S1-2: Disperse 1 g of hydrophobic nano-silica in 100 g of absolute ethanol to obtain S sol. S1-3: Mix the S sol and N sol in a volume ratio of 7:3 and stir evenly to obtain SN73 sol; add 3 wt% resin to the SN73 sol and stir evenly to obtain a mixed sol; use it as the repair sol. Step 2: Preparation of superhydrophobic glass repair coating: Wash the blank glass slide, coat the repair sol on its surface, and dry it by ultraviolet curing to obtain a finished product with a superhydrophobic glass repair coating.

[0034] Performance test: (1) Measure the maximum light transmittance of the coatings prepared in each example and comparative example respectively using a UV spectrophotometer, and the experimental data are shown in Table 1; (2) Measure the water contact angle of the coatings prepared in the examples and comparative example using a contact angle measuring instrument, and the experimental data are shown in Table 1; (3) Repair the worn glass coating with the repair sols prepared in Example 3 and Example 8, and measure its maximum light transmittance and water contact angle. The experimental data are shown in Table 2; (4) Use sand to simulate the pollution on the surface of the photovoltaic module, and use water droplets to clean Example 3 and the blank glass slide. The experimental effect diagram is as Figure 2 shown; (5) Conduct pencil hardness test, cross-cut adhesion test (adhere with 3M tape 5 times), water droplet impact test, and acid (pH = 2 HCl solution) immersion test on Example 3 and Example 8 respectively; conduct an additional alkali (pH = 12 NaOH solution) immersion test on Example 8; the experimental data are as Figure 5 、 Figure 10 、 Figure 11 shown; (6) Conduct a wear test on Example 8, and measure the changes in water contact angle and light transmittance. The experimental data are as Figure 12 shown; Table 1 Item Maximum light transmittance / % Contact angle / ° Example 1 (N) 99.0 22.45 Example 2 (S) 93.4 158.57 Example 3 (SN73) 95.2 153.69 Example 4 (SN19) 97.2 30.78 Example 5 (SN37) 96.5 86.05 Example 6 (SN55) 95.8 107.21 Example 7 (SN91) 94.1 155.12 Example 8 (SN73) 95.1 150.19 Example 9 (SN73) 94.6 151.08 Example 10 (SN73) 92.4 151.75 Blank glass 91.8 57.53 Table 2 Item Maximum light transmittance / % Worn glass 78 Blank glass 91.8 After the repair sol of Example 3 is repaired 88 After the repair sol of Example 8 is adsorbed 90.5 Conclusion: As can be seen from Table 1, the single N sol has the largest maximum light transmittance and the smallest contact angle, and the single S sol has the largest maximum light transmittance and the smallest contact angle; as the S sol increases, the water contact angle of the coating gradually increases and the light transmittance gradually decreases. As the N sol increases, the water contact angle of the coating gradually decreases and the light transmittance of the coating gradually increases; as can be seen from Table 2, after the worn surface is repaired with the repair sol, the maximum light transmittance has increased, and the repair sol with resin added in Example 8 has a better repair effect.

[0035] It can be seen from Figure 1 that after coating the SN73 repair sol of Example 8 on the worn-out glass, it is found that the light transmittance of the worn-out glass reaches 90.5%, which is higher than that of Example 3.

[0036] It can be seen fromFigure 2 It can be seen that the average reflectivity of the blank glass is 8.5%, the average reflectivity of the N coating is 3.1%, the average reflectivity of the S coating is 6.9%, and the average reflectivity of the SN73 coating is 6.1%. This shows that the hydrophobic glass repair coating of the present invention can reduce the glass reflectivity.

[0037] It can be seen from Figure 3 that only a small amount of water droplets can clean the sand on the surface of the SN73 coating in Example 3, while only a small part of the dust on the blank glass is washed away by the water droplets. This shows that the coating of the present invention has good self-cleaning properties.

[0038] It can be seen from Figure 4 that the surface of the N coating in Example 1 has no cracks, is uniform, is composed of small grains, and the maximum height is about 7.96 nanometers, and its root mean square roughness Rq is 2.21 nm. The root mean square roughness Rq of the S coating in Example 2 is 26.13 nm, and the surface is relatively rough. The high roughness results in its hydrophobicity. The root mean square roughness Rq of the SN73 coating in Example 3 is 16.25 nm. SiO2 particles with different particle sizes are cross-linked together to form many irregularly shaped protrusions, resulting in an increase in roughness. While increasing the light transmittance, the hydrophobicity is retained.

[0039] It can be seen from Figure 5 that the surface of the film prepared from the N sol in Example 1 is relatively smooth and has a large number of nano-pores, resulting in its high porosity, thereby increasing the light transmittance. It can be seen from c and d that the surface of the film prepared from the S sol in Example 2 is rough, stacked by nano-particles, and has a small number of large nano-pores. It can be seen from e and f that the surface of the film prepared from the SN73 sol in Example 3 is relatively rough. Different nano-particles are cross-linked and agglomerated together, and there are some nano-pores, making its porosity higher than that of the hydrophobic silica sol, increasing the light transmittance, and at the same time the surface roughness preserves its hydrophobicity.

[0040] It can be seen from Figure 6 that it can be seen from a and b that after the pencil hardness test, the H hardness pencil leaves obvious scratches on the film, while the HB hardness pencil has no obvious scratches, and the pencil hardness of the coating reaches HB. It can be seen from Figure c that after the cross-cut adhesion test, there is no obvious peeling on the film surface, and no damage is observed at the edges of the two cross-scratches, and the adhesion reaches level 1. It can be seen from Figure d that after the water droplet impact test, the light transmittance has no obvious change and only decreases by 0.5%. It can be seen from Figure e that the film can still maintain good light transmittance after being immersed in hydrochloric acid with pH = 2 for 2 and 6 hours, and only decreases by 0.1%. It can be seen from Figure f that the light transmittance only decreases by 0.3% after being adhered with 3M tape 5 times. Thus, it can be seen that the SN73 coating has good mechanical properties.

[0041] It can be seen from Figure 7It can be seen that after applying the SN73 repair sol of Example 3 on the worn-out waste glass, the light transmittance of the waste glass has increased, from 78% to 88%.

[0042] It is known from Figure 8 that the current density (Jsc) of the glass panel after applying the SN73 repair sol of Example 3 has increased from 11.30 to 11.38 mA / cm 2 , the FF has increased from 81.43 to 81.51%, and the solar cell efficiency (PCE) has increased significantly from 22.94% to 23.29%, with an increase of 0.35% and a relative increase of 1.5%.

[0043] It is known from Figure 9 that the transmittance of the coating prepared from the repair sol after adding resin has decreased slightly; it is known from Figure 10 that the coating prepared from the repair sol after adding resin still has superhydrophobicity, and the optimal addition amount of 2wt% resin is comprehensive.

[0044] It is known from Figure 11 that after the coating prepared from the sol with 2% resin added in Example 8 has undergone the water droplet impact test, the transmittance and hydrolysis contact angle of the coating have not changed. After being soaked in acid (pH = 2 HCl solution) and alkali (pH = 12 NaOH solution) for 24 hours, the transmittance has decreased by about 0.5%, and the water contact angles have decreased to 137.54° and 132.67° respectively. It can be seen that it has good resistance to rain erosion and also has good resistance to chemical solutions.

[0045] It is known from Figure 12 that the adhesion of the coating prepared from the sol with 2% resin added in Example 8 reaches Grade 1. A 3H pencil can scratch the coating, while a 2H pencil cannot scratch the coating. The pencil hardness reaches 2H, and there is a significant improvement in hardness compared to Example 3 without added resin.

[0046] It is known from Figure 13 that the water contact angle and light transmittance of the coating prepared from the sol with 2% resin added in Example 8 gradually decrease with each wear. After the coating has undergone 5 wear tests, the water contact angle has become 104.01°, and the light transmittance has decreased to 92.1%. This shows that the coating has good wear resistance and still maintains a certain degree of hydrophobicity and good light transmittance.

[0047] In summary, the present invention prepares S sol and N sol, mixes them in a volume ratio of 7:3 to obtain SN73 sol, and then adds 2wt% resin. The prepared coating can repair worn glass, has good light transmittance and superhydrophobic effect, and also has certain wear resistance, chemical resistance, good hardness and adhesion.

[0048] Finally, it should be noted that the above are only the preferred embodiments of the present invention and are not intended to limit the present invention. Although the present invention has been described in detail with reference to the foregoing embodiments, those skilled in the art can still modify the technical solutions recorded in the foregoing embodiments or perform equivalent replacements for some of the technical features. Any modifications, equivalent replacements, improvements, etc. made within the spirit and principle of the present invention shall be included within the protection scope of the present invention.

Claims

1. A preparation process for a super-hydrophobic glass repair coating, characterized in that: The following steps are involved: Step 1: Preparation of repair sol: S1-1: (1) Disperse tetraethyl orthosilicate in anhydrous ethanol and stir magnetically for 25-30 min to obtain solution A; (2) Mix ammonia water, deionized water and anhydrous ethanol and stir magnetically for 25-30 min at room temperature to obtain solution B; (3) Add solution B dropwise to solution A and stir magnetically for 2-3 h at room temperature; and age the obtained solution at room temperature for 3 days to obtain N sol; S1-2: dispersing hydrophobic nano-silica in anhydrous ethanol to obtain S sol; S1-3: The S sol and the N sol are mixed and stirred evenly to obtain the SN sol; Use it as repair sol; Step 2: Preparation of super-hydrophobic glass repair coating: The worn glass is cleaned, the repair sol is coated on its surface, and then ultraviolet curing and drying are performed to obtain a finished product containing a super-hydrophobic glass repair coating.

2. A preparation process for a super-hydrophobic glass repair coating according to claim 1, characterized in that: In step S1-1: the solution A comprises tetraethyl orthosilicate and anhydrous ethanol in a volume ratio of 7:33-34; the solution B comprises ammonia water, deionized water and anhydrous ethanol in a volume ratio of 1:1.1-1.2:33.5-34; the S sol comprises hydrophobic nano-silica and anhydrous ethanol in a mass ratio of 1-2:

100.

3. A preparation process for a super-hydrophobic glass repair coating according to claim 1, characterized in that: In step S1-3: the SN series sol includes S sol and N sol in a volume ratio of 7:

3.

4. The preparation process of a super-hydrophobic glass repair coating according to claim 1, characterized in that: The preparation method of the hydrophobic nano-silica comprises the following steps: (1) adding nano-silica and deionized water to anhydrous ethanol for uniform ultrasonic dispersion, adding 3-aminopropyltriethoxysilane, heating and stirring at 50-60° C. for 2-4 hours, centrifuging, washing, and drying to obtain amino-modified nano-silica; (2) adding amino-modified nano-silica to anhydrous ethanol and ultrasonically dispersing the nano-silica uniformly, adding oleic acid and an activator, heating and stirring at 50-60°C for 3-4 hours, centrifuging, washing, and drying to obtain oleic acid-modified nano-silica; (3) Add oleic acid-modified nano-silica into anhydrous ethanol and disperse it evenly by ultrasonication, add hexamethyldisilazane, and stir at 50-60°C for 2.5-3.5 hours to obtain hydrophobic nano-silica.

5. A process for preparing a super-hydrophobic glass repair coating according to claim 4, characterized in that: The amino-type nano-silica comprises the following raw materials in parts by weight: 1-2 parts of nano-silica, 10-20 parts of deionized water, 30-40 parts of anhydrous ethanol, and 0.3-0.5 parts of 3-aminopropyltriethoxysilane; The oleic acid-modified nano-silica comprises the following raw materials in parts by weight: 1-2 parts of amino-modified nano-silica, 30-40 parts of anhydrous ethanol, 0.45-0.55 parts of oleic acid, and 0.5-0.6 parts of an activator; The hydrophobic nano-silica comprises the following raw materials in parts by weight: 1-2 parts of oleic acid-modified nano-silica, 30-40 parts of anhydrous ethanol, and 0.12-0.14 parts of hexamethyldisilazane.

6. The preparation process of a super-hydrophobic glass repair coating according to claim 1, characterized in that: In step S1-3: the S sol and the N sol are mixed and stirred evenly to obtain the SN sol; the resin is added and stirred evenly to obtain the mixed sol; and the mixed sol is used as the repair sol.

7. A process for preparing a super-hydrophobic glass repair coating according to claim 6, characterized in that: The amount of the resin added is 1-3 wt % of the SN sol.

8. The process for preparing a super-hydrophobic glass repair coating according to claim 6, characterized in that: The preparation method of the resin comprises the following steps: (1) removing water from polytetramethylene ether diol at 140° C. and then keeping the temperature at 50° C., adding 2-4 wt % concentrated phosphoric acid to obtain a monomer mixture; (2) Toluene-2,4-diisocyanate and dibutyltin dilaurate are uniformly mixed, the monomer mixture is slowly added dropwise, and the mixture is stirred at 50-55° C. for 3-4 hours to obtain polyurethane; (3) The polyurethane, 1,4-butanediol and pentaethylene glycol were mixed evenly, and the mixture was stirred at 55-65°C for chain extension for 2-3 hours, and hydroxyethyl acrylate and p-tert-butylcatechol were added, and the end-capping reaction was carried out at 60-70°C for 2-3 hours to obtain a polyurethane prepolymer; (4) 5,5-di(propane-2-ylmercapto)pentane-1,2,3-triol, thiourea and 1 mol / L hydrochloric acid were mixed evenly, heated and stirred at 90-100°C for 1-1.5 h, cooled to 50-60°C, adjusted the pH to 7.5-8.5 under a nitrogen atmosphere, stirred for 1-1.5 h, allowed to stand for stratification, and the lower organic phase was removed and purified by distillation to obtain a cross-linking agent; (5) The polyurethane prepolymer, 2-hydroxyethyl methacrylate, isobornyl acrylate, a crosslinking agent, and a photoinitiator are uniformly mixed to obtain a resin.

9. A process for preparing a super-hydrophobic glass repair coating according to claim 8, characterized in that: The polyurethane comprises the following raw materials in parts by weight: 4 to 4.5 parts of toluene-2,4-diisocyanate, 19.5 to 20.5 parts of a monomer mixture, and 0.1 to 0.3 parts of dibutyltin dilaurate; The polyurethane prepolymer comprises the following raw materials in parts by weight: 24-25 parts of polyurethane, 0.2-0.3 parts of 1,4-butanediol, 0.4-0.5 parts of pentaethylene glycol, 2.8-3 parts of hydroxyethyl acrylate, and 0.04-0.05 parts of p-tert-butylcatechol; The cross-linking agent includes the following raw materials in parts by weight: 13 to 13.5 parts of 5,5-di(propane-2-ylmercapto)pentane-1,2,3-triol, 11.5 to 12 parts of thiourea, and 30 parts of 1 mol / L hydrochloric acid; The resin comprises a polyurethane prepolymer, 2-hydroxyethyl methacrylate, isobornyl acrylate, a crosslinking agent and a photoinitiator in a mass ratio of 45-65:20-25:5-10:3-4:3.

5.

10. A super-hydrophobic glass repair coating, characterized in that: The super-hydrophobic glass repair coating is prepared by the preparation process of any one of claims 1 to 9.

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