A transparent, flexible, stain-resistant coating and method of making the same

Abstract

The application discloses a kind of transparent flexible antifouling coating and preparation method thereof, wherein preparation method includes the following steps: S1. preparation of antifouling hydrophobic monomer;S2. preparation of epoxy-based silicone resin;S3. antifouling hydrophobic monomer and epoxy-based silicone resin are reacted under acidic conditions in solvent to obtain epoxy-based silicone resin with antifouling hydrophobic structure;S4. preparation of alkyl epoxy-based silicone resin;S5. preparation of hydrolysable monomer;S6. hydrolysable monomer, amino silane coupling agent and water are reacted in solvent to obtain amino silicone resin with hydrolysable structure;S7. epoxy-based silicone resin with antifouling hydrophobic structure, alkyl epoxy-based silicone resin and amino silicone resin with hydrolysable structure are reacted in solvent to obtain silicon-based antifouling coating;S8. silicon-based antifouling coating is coated on the surface of substrate, and the substrate is placed to obtain.The coating prepared by the application has good antibacterial, diatom adhesion and antifouling performance, and the coating has high optical transparency and flexibility.

Description

Technical Field

[0001] This invention relates to the field of marine antifouling coatings, specifically to a transparent and flexible antifouling coating and its preparation method. Background Technology

[0002] With the deepening of economic globalization, the development level of marine industries, the ability to exploit marine resources, and the strength to maintain marine security have become increasingly important. However, the accumulation of marine fouling on the surfaces of ships and equipment has led to increased ship navigation resistance and energy consumption, equipment malfunctions and reduced lifespan, and decreased power and signal inaccuracy in underwater transmission equipment, significantly hindering the development of marine industries. Therefore, there is a need to develop an antifouling coating for the surface protection of facilities and equipment such as ships, underwater sensors, and marine photovoltaic panels. For specific application scenarios, the coating also needs to possess high optical transparency and flexibility.

[0003] However, the antifouling coatings currently mainly used are release coatings that release toxic substances or synthetic polymers into water. The toxic substances and polymers released into water may have adverse effects on the environment and human health, which does not meet the overall development requirements of green and environmental protection. Therefore, this invention develops an antifouling coating based on non-toxic substances, which has the characteristics of high optical transparency and flexibility, expanding the application fields and usage scenarios of the coating.

[0004] To prepare surface protection for applications such as glass in buildings, mobile phone screens, and automotive glass, Zhang Youfa, in his invention patent 202310236478.3, "Modified UV Varnish and Method for Preparing Transparent Antifouling Coatings Based on Modified Varnish," used fluorinated monomers and fluorosilanes to modify UV varnishes and prepared transparent antifouling coatings. The antifouling coating prepared by this method possesses characteristics of transparency and low surface energy; however, its application in marine antifouling requires further verification, and its flexibility needs to be tested.

[0005] To develop and apply transparent antifouling coatings for marine applications, Sun Jiawen, in his invention patent 202311017564.1, "A Transparent Self-Lubricating Organosilicon Hybrid Antifouling Coating with Negatively Charged Surface and Its Preparation Method," used nanocellulose, hydroxy acids, and functional fluorinated / siloxanes as raw materials to prepare a transparent self-lubricating organosilicon hybrid antifouling coating with a negatively charged surface through a sol-gel reaction. The lubricant used in this method may be released in the marine environment, and its recalcitrant nature can lead to certain problems.

[0006] Therefore, there is a need to develop a method for preparing a marine antifouling coating with high optical transparency that avoids the use of highly volatile solvents, has good substrate adhesion performance, does not release toxic components into water, and does not synthesize polymers. Summary of the Invention

[0007] In view of this, in order to solve the above-mentioned technical problems, the purpose of this invention is to provide a transparent and flexible antifouling coating and its preparation method. The coating obtained has good antibacterial and antifouling properties against diatom adhesion, and the coating has the characteristics of high optical transparency and flexibility.

[0008] The technical solution adopted is as follows:

[0009] A method for preparing a transparent, flexible, and antifouling coating includes the following steps:

[0010] S1. Preparation of antifouling and hydrophobic monomers: Thiols, natural extracts, fluorinated acrylates and photoinitiators are dissolved in a solvent and reacted under ultraviolet light to generate antifouling and hydrophobic monomers;

[0011] Technical Description: The antifouling and hydrophobic monomer prepared by this invention is a monomer that provides antifouling functionality and low surface energy properties by preparing a thiol-olefin click polymerization reaction initiated by ultraviolet light. It contains the antifouling activity of natural extracts and the hydrophobic properties of fluoropolymers.

[0012] S2. Epoxy-based silicone resin is obtained by reacting an epoxy-based silane coupling agent in an acidic solvent.

[0013] Technical Description: S2 is formed by the hydrolysis of silane coupling agent under acidic conditions to form abundant silanol groups. Then, the silanol groups undergo a condensation reaction to form a cross-linked network. Due to the presence of epoxy side chains, a hyperbranched silicone resin structure with abundant silanol and epoxy groups is formed.

[0014] S3. React the antifouling and hydrophobic monomer in S1 with the epoxy-based silicone resin in S2 under acidic conditions in a solvent to obtain an epoxy-based silicone resin with an antifouling and hydrophobic structure.

[0015] Technical Description: The antifouling and hydrophobic monomer undergoes a hydrolysis reaction in an acidic system to form silanol groups. The silanol groups in the monomer and the silanol groups in the epoxy silicone resin undergo a dehydration condensation reaction, while the fluorinated segments and epoxy groups containing natural extracts are retained, forming a hyperbranched epoxy silicone resin with hydrophobic and antifouling active side chains.

[0016] S4. An alkylepoxy silicone resin is obtained by reacting an epoxy silane coupling agent and an alkyl silane coupling agent in an acidic solvent.

[0017] Technical Description: Silane coupling agents undergo hydrolysis in an acidic system to form silanol groups. The silanol groups then undergo dehydration condensation to form hyperbranched epoxy silicone resins with alkyl side chains.

[0018] S5. Preparation of hydrolyzable monomers: The aminosilane coupling agent and the acrylate monomer are reacted in a solvent to obtain the hydrolyzable monomers;

[0019] Technical Description: The amino group of the aminosilane coupling agent undergoes a Michael addition reaction with the double bond in the acrylate monomer to generate a hydrolyzable propionate structure. Under seawater induction, this structure generates a zwitterionic structure with a positively charged amino group and a negatively charged carboxylic acid group on the same side chain. This structure has strong hydrophilic properties and provides hydrophilic properties to the coating.

[0020] S6. React the hydrolyzable monomer, aminosilane coupling agent and water in S5 in a solvent to obtain an aminosilicone resin with a hydrolyzable structure;

[0021] Technical Description: Silane coupling agents undergo hydrolysis in the presence of water to form silanol groups. The silanol groups then undergo dehydration condensation to form a hyperbranched aminosilicone resin structure with hydrolyzable side chains.

[0022] S7. React the epoxy-based antifouling coating obtained by reacting the epoxy-based silicone resin with antifouling and hydrophobic structure in S3, the alkyl-based epoxy-based silicone resin in S4, and the amino-based silicone resin with hydrolyzable structure in S6 in a solvent.

[0023] Technical Description: Hyperbranched epoxy silicone resin with hydrophobic and antifouling active side chains, hyperbranched epoxy silicone resin with alkyl side chains, and hyperbranched amino silicone resin with hydrolyzable side chains react with epoxy and amino groups to form a cross-linked polymer; at the same time, the silanol groups in the silicone resin structure also undergo dehydration condensation reaction to generate a cross-linked structure, thus forming a cross-linked polymer.

[0024] S8. Apply the silicone-based antifouling coating from S7 to the surface of the substrate, place the substrate, and form a fully cured transparent antifouling coating.

[0025] Technical Description: The cross-linked polymer formed in S8 contains abundant silanol groups and hydroxyl groups generated by the reaction of epoxy groups and amino groups. The above-mentioned hydroxyl groups and hydroxyl groups on the substrate surface undergo cross-linking reactions, and the coating is firmly cross-linked on the substrate surface. Placing it at a certain temperature is to allow the solvent used in the reaction and the water molecules formed during the cross-linking reaction to evaporate, thereby achieving further cross-linking of the polymer and forming a stable antifouling coating.

[0026] Furthermore, in S1, the natural extract includes one or more of cannabidiol, linalool, capsaicin, citronellol, isoborneol acrylate, menthol, and borneol; the fluorinated acrylate includes one or more of trifluoroethyl methacrylate, hexafluorobutyl methacrylate, hexafluoroisopropyl methacrylate, dodecafluoroheptyl acrylate, and dodecafluoroheptyl methacrylate; the solvent is one or both of methanol and ethanol; the mass ratio of thiol, natural extract, fluorinated acrylate, and solvent is 1:(0.01-4):(0.01-4):(2-10).

[0027] Furthermore, in S2, the epoxy silane coupling agent includes one or both of γ-glycidyl etheroxypropyltrimethoxysilane and γ-glycidyl etheroxypropyltriethoxysilane; the mass ratio of epoxy silane coupling agent to solvent is 1:(0.5-3); the solvent includes one or more of methanol, ethanol, and isopropanol; the acid used is one or more of hydrochloric acid, oxalic acid, and acetic acid; the reaction temperature is 25-80℃; and the reaction time is 0.5-12h.

[0028] Furthermore, in S3, the mass ratio of antifouling and hydrophobic monomer to epoxy-based silicone resin is (0.01-1.5):1; the reaction temperature is 25-80℃; and the reaction time is 0.5-12h.

[0029] Further, in S4, the epoxy silane coupling agent includes one or both of γ-glycidoxypropyltrimethoxysilane and γ-glycidoxypropyltriethoxysilane; the alkyl silane coupling agent includes methyltrimethoxysilane, methyltriethoxysilane, ethyltrimethoxysilane, propyltrimethoxysilane, butyltrimethoxysilane, pentyltrimethoxysilane, hexyltrimethoxysilane, isobutyltrimethoxysilane, isooctyltrimethoxysilane, octyltrimethoxysilane, decyltrimethoxysilane, cyclopentyltrimethoxysilane, cyclohexyltrimethoxysilane, ethyltriethoxysilane, and propyltriethoxysilane. One or more of the following: silane, butyltriethoxysilane, pentyltriethoxysilane, hexyltriethoxysilane, isobutyltriethoxysilane, isooctyltriethoxysilane, octyltriethoxysilane, decyltriethoxysilane, cyclopentyltriethoxysilane, and cyclohexyltriethoxysilane; solvent including one or more of methanol, ethanol, and isopropanol; the mass ratio of epoxysilane coupling agent or alkylsilane coupling agent to solvent is 1:(0.05-0.6):(0.8-3); the acid used is one or more of hydrochloric acid, oxalic acid, and acetic acid; the reaction temperature is 25-80℃; and the reaction time is 0.5-24h.

[0030] Furthermore, in S5, the aminosilane coupling agent is 3-aminopropyltrimethoxysilane, 3-aminopropyltriethoxysilane, anilinemethyltrimethoxysilane, m-aminophenyltrimethoxysilane, N-aminoethyl-γ-aminopropyltrimethoxysilane, cyclohexylaminopropyltrimethoxysilane, 4-amino-3,3-dimethylbutyltrimethoxysilane, N-(2-N-benzylaminoethyl)-3-aminopropyltrimethoxysilane, or 3-[2-(2-aminoethylamino)ethylamino]propyl-trimethoxysilane. One or more of the following alkanes; acrylate monomers include one or more of methyl acrylate, ethyl acrylate, decyl acrylate, benzyl acrylate, phenyl acrylate, tert-butyl acrylate, octadecyl acrylate, 2-octyl acrylate, butyl acrylate, and hexyl acrylate; solvents include one or more of methanol, ethanol, and isopropanol; the mass ratio of aminosilane coupling agent, acrylate monomer, and solvent is 1:(0.25-4):(1-4); the reaction time is 12-144 h; and the reaction temperature is 20-50℃.

[0031] Furthermore, in S6, the aminosilane coupling agent includes one or both of 3-aminopropyltrimethoxysilane and 3-aminopropyltriethoxysilane; the solvent includes one or more of methanol, ethanol, and isopropanol; the mass ratio of aminosilane coupling agent, hydrolyzable monomer, water, and solvent is 1:(0.01-1):(0.05-0.3):(0.5-4); the reaction temperature is 20-80℃; and the reaction time is 1-24h.

[0032] Furthermore, in S7, the solvent includes one or more of methanol, ethanol, and isopropanol; the mass ratio of epoxy-based silicone resin with antifouling and hydrophobic structure, alkyl-based silicone resin, and amino-based silicone resin with hydrolyzable structure to the solvent is 1:(0.5-2):(0.5-2):(0.5-4); the reaction temperature is 20-50℃; and the reaction time is 0.1-2h.

[0033] Furthermore, in S8, the coating method includes one or more of brush coating, scraping coating, spraying coating, spin coating, drip coating, and dip coating; the substrate includes one of steel sheet, glass sheet, ceramic sheet, polymethyl methacrylate sheet, polycarbonate sheet, and polyethylene terephthalate sheet; the substrate standing temperature is 20-80℃; and the substrate standing time is more than 0.5h.

[0034] The antifouling coating prepared by the above method can be applied to the surface of ship equipment in the marine shipbuilding industry, as well as to the transparent viewing window surface of underwater vehicles and underwater detectors, with the aim of preventing many problems caused by the adhesion of marine fouling.

[0035] This invention prepares a marine antifouling coating with high optical transparency and flexibility. It utilizes a UV-initiated thiol-olefin click reaction, employing natural extracts as the main antifouling active ingredient and fluorinated groups as hydrophobic groups to prepare hydrophobic antifouling active monomers. Then, through hydrolysis and condensation reactions of silane coupling agents in an acidic system, a hyperbranched epoxy-based silicone resin with hydrophobic antifouling active groups is prepared. Next, through hydrolysis and condensation reactions of silane coupling agents in an acidic system, a hyperbranched epoxy-based silicone resin with alkyl side chains is prepared. Subsequently, using a Michael addition reaction of an amino coupling agent and an acrylate monomer, functional groups capable of hydrolyzing to form zwitterions in a seawater environment are prepared. Through hydrolysis and condensation reactions of an aminosilane coupling agent, a hyperbranched amino-based silicone resin with hydrolyzable groups is prepared. Finally, through the reaction of amino and epoxy groups and the dehydration condensation reaction of silanol groups, a highly crosslinked polymer antifouling coating is prepared.

[0036] The antifouling coating prepared by this invention possesses a synergistic triple antifouling effect: 1) it provides a first layer of antifouling effect through the antifouling activity of natural extracts; 2) it achieves a second layer of antifouling effect through the dynamic surface properties of hydrolyzable groups; and 3) it achieves a third layer of antifouling effect through the amphiphilic surface composed of hydrophobic groups and hydrophilic groups formed after hydrolysis. Furthermore, the coating's high optical transparency and flexibility are important foundations for its application in multiple fields.

[0037] This invention provides an antifouling coating with high optical transparency, good flexibility, good substrate adhesion, and excellent antifouling properties. It is suitable for protecting the surfaces of ships and underwater pipelines, as well as for protecting surfaces requiring high transparency, such as underwater detectors, underwater vehicles, underwater sensors, and marine photovoltaic equipment. The antifouling active natural extracts used in this invention provide protection; their chemical cross-linking within the polymer network does not release into water, making them environmentally friendly. Simultaneously, the hydrolyzable groups used in this invention form a dynamic surface in seawater, and their hydrolysis produces small-molecule alcohols that are harmless to the marine environment. The preparation of this antifouling coating does not use highly volatile or highly toxic solvents, avoiding related problems. Furthermore, the coating can be cured using both room temperature and heat curing methods, making it suitable for surface antifouling in various scenarios.

[0038] This invention uses fluorine-containing groups as hydrophobic antifouling groups and citronellol as active antifouling groups. It utilizes the hydrolysis reaction of methyl 3-((3-(methoxysilyl)propyl)amino)propionate, which can be hydrolyzed in a seawater environment, to generate zwitterionic structures in situ as hydrophilic antifouling groups. The coating has good antibacterial and anti-diatom adhesion antifouling properties. The coating has high optical transparency and flexibility and can be applied to underwater sightseeing cable cars, underwater detection instruments and other fields in the marine industry. It can also be used for surface protection of marine photovoltaic equipment and underwater sensors.

[0039] The purpose of this invention is to address the problems of increased navigation resistance, decreased resource development efficiency, and inaccurate signal transmission caused by marine fouling during marine shipping, marine resource development, and underwater signal transmission. This invention utilizes fluoropolymers to provide low surface energy, natural extracts as antifouling active components, and zwitterionic groups formed by hydrolysis in seawater to provide hydrophilic properties, thereby achieving a gradually forming amphiphilic antifouling coating with high antibacterial activity, diatom inhibition, and mussel repellency.

[0040] Compared with the existing technology, the present invention has the following advantages:

[0041] 1. The present invention uses natural extracts grafted onto polymers through chemical cross-linking, which eliminates the problem of release into water, ensures the antifouling activity of the coating for a long time, achieves the first antifouling effect, and is also environmentally friendly.

[0042] 2. This invention uses groups that hydrolyze to form zwitterions in a seawater environment as another antifouling function, achieving a second layer of antifouling effect through the micro-dynamic characteristics of the hydrolysis process.

[0043] 3. The material used in this invention has hydrophobic groups and gradually formed hydrophilic groups, which gradually transform the coating interface into amphiphilic properties, thus achieving a third layer of antifouling effect.

[0044] 4. The composite of hyperbranched silicon-based materials used in this invention not only gives the material high optical transparency but also flexibility, thus expanding the application scenarios of the coating.

[0045] 5. The solvents used in the preparation of materials in this invention are all low-toxicity alcohol solvents, and the synthesis process is environmentally friendly. Attached Figure Description

[0046] Figure 1 Transparency test results of glass slides, coatings prepared in Example 1 and Example 2 under ultraviolet-visible light spectroscopy.

[0047] Figure 2 The image shows the coating prepared in Example 1 applied to the surface of a polymethyl methacrylate sheet and a glass sheet.

[0048] Figure 3 The coating prepared in Example 1 is applied to the surface of a polyethylene terephthalate sheet, which is then extruded into specific letters (H, E, and U) and rolled into a circle. This is a picture of the actual product after it is opened.

[0049] Figure 4Microscopic images of the coatings prepared in Examples 1 and 2 applied to the surface of polyethylene terephthalate sheets before and after being bent into a U-shape 100 times. Detailed Implementation

[0050] The present invention will be described in detail below through specific embodiments. However, the uses and purposes of these exemplary embodiments are only for illustrating the present invention and do not constitute any limitation on the actual protection scope of the present invention, nor are they intended to limit the protection scope of the present invention to this.

[0051] Example 1

[0052] This embodiment provides a method for preparing a transparent, flexible, and antifouling coating, which includes the following steps:

[0053] S1. 1.96g of (3-mercaptopropyl)trimethoxysilane, 3.12g of citronellol, 7.5g of hexafluorobutyl methacrylate and 10g of ethanol were stirred, and then 0.38g of benzoin dimethyl ether was added. Then, under the initiation of ultraviolet light, an antifouling and hydrophobic monomer was obtained.

[0054] S2. 23.6 g of γ-glycidyl etheroxypropyltrimethoxysilane, 12.0 g of ethanol, 2.2 g of 1 M HCl solution and 2 g of deionized water were thoroughly mixed and reacted at 60 °C for 4 h to obtain epoxy-based silicone resin.

[0055] S3. Add 9.0g of antifouling and hydrophobic monomer, 1.1g of 1M HCl solution, 1g of deionized water and 4g of ethanol to the epoxy-based silicone resin prepared in S2, and react at 60℃ for 4h to obtain epoxy-based silicone resin with antifouling and hydrophobic structure.

[0056] S4. Mix 23.6 g of γ-glycidyl oxypropyltrimethoxysilane, 9 g of methyltrimethoxysilane, 3.3 g of 1M HCl solution, 3 g of deionized water and 16.0 g of ethanol, and react at 60 °C for 8 h to obtain alkyl epoxy silicone resin.

[0057] S5. Preparation of hydrolyzable monomer: 17.9 g of 3-aminopropyltrimethoxysilane, 10.3 g of acrylate monomer and 31.6 g of methanol were mixed and stirred in an ice-water bath, reacted at 25 °C for 48 h, and the solvent was removed by heating at 60 °C to obtain the hydrolyzable monomer.

[0058] S6. Mix and stir 8.0 g of hydrolyzable monomer, 12.0 g of 3-aminopropyltrimethoxysilane, 2.0 g of deionized water and 16.0 g of ethanol, and react at 60 °C for 4 h to obtain an amino silicone resin with a hydrolyzable structure.

[0059] S7. Mix 2.0g of the epoxy-based silicone resin with antifouling and hydrophobic structure obtained in S3, 2.0g of the alkyl-based silicone resin obtained in S4, and 2.0g of the amino-based silicone resin with hydrolyzable structure obtained in S6 with 2.0g of ethanol and stir. React at 25°C for 0.5h to obtain a silicone-based antifouling coating.

[0060] S8. Apply the silicon-based antifouling coating obtained in S7 to the surface of a glass slide by spin coating, and place the glass slide coated with the silicon-based antifouling coating at 60°C for 4 hours to form a fully cured coating.

[0061] The relevant properties and shapes of the tested coatings are as follows:

[0062] Bacterial adhesion inhibition performance test method. The coating prepared in Example 1 was immersed in artificial seawater for 4 days beforehand. Glass slides without the antifouling coating and samples coated with the coating from Example 1 were placed in bacterial culture medium of the same concentration for 24 hours. After the bacteria attached to the surfaces of the glass slides and the coated samples from Example 1 were washed off, they were incubated on solid culture medium for 24 hours. The number of bacterial colonies attached to the surfaces of the glass slides and the coated samples from Example 1 was calculated, and the number of bacterial colonies on the glass slide surface was used as the comparison standard. The bacterial adhesion reduction rate on the coating surface was calculated, which is the bacterial adhesion inhibition rate of the coating. The corresponding bacterial adhesion inhibition rates are as follows:

[0063] Results of bacterial adhesion inhibition performance test:

[0064] Antibacterial rate of *Pseudomonas aeruginosa*: 94.8%

[0065] Antibacterial rate against Escherichia coli: 95.8%

[0066] Antibacterial rate against Staphylococcus aureus: 97.9%

[0067] Test method for diatom adhesion inhibition performance. Glass slides without antifouling coating and samples coated with the coating from Example 1 were placed in the same concentration of *Dendrobium nobile* diatom culture medium for 4 days. The number of diatoms adhering to the surface of the glass slides and the coated samples from Example 1 was observed and measured using a fluorescence microscope. The number of diatoms adhering to the glass slide surface was used as the comparison standard. The diatom adhesion reduction rate on the coating surface was calculated, which is the diatom adhesion inhibition rate of the coating. The corresponding diatom adhesion inhibition rates are as follows:

[0068] Diatomaceous earth adhesion inhibition performance test results:

[0069] Double-browed algae: 95.8%

[0070] The adhesion test result of the coating on the glass slide surface, conducted according to ASTM D4541-09 standard, is 1.3 MPa.

[0071] Flexibility Test Method. The silicone-based antifouling coating prepared in Example 1 was spin-coated onto the surface of polyethylene terephthalate and allowed to cure completely at 25°C for 144 hours. The coating was bent into a U-shape and then unfolded, repeated 100 times. The surface of the coating was observed for cracking and peeling using an optical microscope, and photographs were taken. The surface morphology before and after the bending experiment was compared to demonstrate the flexibility of the coating. Experimental Results. Test Results: The coating remained highly uniform and intact after 100 bending cycles.

[0072] Example 2

[0073] Referring to Example 1, the difference is that in S6 of this example, the mass of the hydrolyzable monomer added is 6.0 g, and the mass of 3-aminopropyltrimethoxysilane added is 14 g. The remaining steps remain unchanged.

[0074] Results of bacterial adhesion inhibition performance test:

[0075] Antibacterial rate of *Pseudomonas aeruginosa* in Xiamen: 94.4%

[0076] Antibacterial rate against Escherichia coli: 94.8%

[0077] Antibacterial rate against Staphylococcus aureus: 97.2%

[0078] Diatomaceous earth adhesion inhibition performance test results:

[0079] Double-browed algae: 95.9%

[0080] The adhesion test result of the coating on the glass slide surface, conducted according to ASTM D4541-09 standard, is 1.3 MPa.

[0081] Flexibility test results: The coating remained highly uniform and intact after being bent 100 times.

[0082] Figure 1 The results of the transparency tests of the glass slide, the coating prepared in Example 1, and the coating prepared in Example 2 under ultraviolet-visible light spectrum are shown in the figure. As can be seen from the results, the coatings all have optical transparency of more than 95% in the wavelength range of 350-800nm.

[0083] Figure 2 The images show actual photos of the coating prepared in Example 1 applied to the surfaces of polymethyl methacrylate sheets and glass sheets, demonstrating the good transparency of the coating.

[0084] Figure 3 The coating prepared in Example 1 was applied to the surface of a polyethylene terephthalate sheet. The coating was extruded into specific letters (H, E, and U) and then rolled into a circle. The actual image shows the coating after it was opened, demonstrating the flexibility and transparency of the coating.

[0085] Figure 4 Microscopic photographs of the coatings prepared in Examples 1 and 2 applied to the surface of polyethylene terephthalate sheets before and after being bent into a U-shape 100 times demonstrate the flexibility of the coatings.

[0086] The results of the embodiments demonstrate that the antifouling coating prepared by the method of the present invention exhibits high optical transparency within the wavelength range of 350-800 nm, with a transmittance exceeding 90%. Furthermore, the coating maintains high uniformity and transparency even after 100 bending cycles. Antibacterial adhesion tests show that the coating, after immersion in artificial seawater for 4 days, resists over 90% bacterial adhesion. Antidiatom adhesion tests show that the coating, after immersion in a diatom solution for 4 days, still inhibits over 85% diatom adhesion.

[0087] The detailed descriptions listed above are merely specific illustrations of feasible embodiments of the present invention and are not intended to limit the scope of protection of the present invention. All equivalent embodiments or modifications made without departing from the spirit of the present invention should be included within the scope of protection of the present invention.

Claims

1. A method for preparing a transparent, flexible, and antifouling coating, characterized in that, Includes the following steps: S1. A thiol, a natural extract, a fluorinated acrylate, and a photoinitiator are dissolved in a solvent and reacted under ultraviolet light to generate an antifouling and hydrophobic monomer; wherein the mass ratio of the thiol, the natural extract, the fluorinated acrylate, and the solvent is 1:(0.01-4):(0.01-4):(2-10); the thiol is (3-mercaptopropyl)trimethoxysilane; the natural extract is citronellol; and the fluorinated acrylate is hexafluorobutyl methacrylate. S2. An epoxy-based silicone resin is obtained by reacting an epoxy-based silane coupling agent in an acidic solvent; wherein the mass ratio of the epoxy-based silane coupling agent to the solvent is 1:(0.5-3); the reaction temperature is 25-80℃; the reaction time is 0.5-12h; and the epoxy-based silane coupling agent is γ-glycidoxypropyltrimethoxysilane. S3. The antifouling and hydrophobic monomer in S1 and the epoxy-based silicone resin in S2 are reacted in an acidic solvent to obtain an epoxy-based silicone resin with an antifouling and hydrophobic structure; wherein the mass ratio of the antifouling and hydrophobic monomer to the epoxy-based silicone resin is (0.01-1.5):1; the reaction temperature is 25-80℃; and the reaction time is 0.5-12h. S4. An alkylepoxysilane coupling agent and an alkylsilane coupling agent are reacted in a solvent under acidic conditions to obtain an alkylepoxysilane resin; wherein the mass ratio of the epoxysilane coupling agent, the alkylsilane coupling agent and the solvent is 1:(0.05-0.6):(0.8-3); the reaction temperature is 25-80℃; the reaction time is 0.5-24h; the epoxysilane coupling agent is γ-glycidoxypropyltrimethoxysilane; and the alkylsilane coupling agent is methyltrimethoxysilane. S5. An aminosilane coupling agent and an acrylate monomer are reacted in a solvent to obtain a hydrolyzable monomer; wherein the mass ratio of the aminosilane coupling agent, the acrylate monomer, and the solvent is 1:(0.25-4):(1-4); the reaction time is 12-144 h; the reaction temperature is 20-50 °C; the aminosilane coupling agent is 3-aminopropyltrimethoxysilane; the acrylate monomer includes one or more of methyl acrylate, ethyl acrylate, decyl acrylate, benzyl acrylate, phenyl acrylate, tert-butyl acrylate, octadecyl acrylate, 2-octyl acrylate, butyl acrylate, and hexyl acrylate; S6. The hydrolyzable monomer, aminosilane coupling agent, and water from S5 are reacted in a solvent to obtain an aminosilicone resin with a hydrolyzable structure; wherein the mass ratio of aminosilane coupling agent, hydrolyzable monomer, water, and solvent is 1:(0.01-1):(0.05-0.3):(0.5-4); the reaction temperature is 20-80℃; and the reaction time is 1-24h. S7. React the epoxy-based antifouling silicone resin with antifouling and hydrophobic structure in S3, the alkyl-based epoxy-based silicone resin in S4, and the amino-based silicone resin with hydrolyzable structure in S6 in a solvent to obtain a silicone-based antifouling coating; wherein the mass ratio of the epoxy-based silicone resin with antifouling and hydrophobic structure, the alkyl-based epoxy-based silicone resin, and the amino-based silicone resin with hydrolyzable structure to the solvent is 1:(0.5-2):(0.5-2):(0.5-4); the reaction temperature is 20-50℃; and the reaction time is 0.1-2h. S8. Apply the silicone-based antifouling coating from S7 to the surface of the substrate, place the substrate, and form a fully cured transparent antifouling coating.

2. The method for preparing the transparent, flexible, and antifouling coating according to claim 1, characterized in that: In S1, the solvent is one or both of methanol and ethanol.

3. The method for preparing the transparent, flexible, and antifouling coating according to claim 1, characterized in that: In S2, the solvent includes one or more of methanol, ethanol, and isopropanol; the acid used is one or more of hydrochloric acid, oxalic acid, and acetic acid.

4. The method for preparing the transparent, flexible, and antifouling coating according to claim 1, characterized in that: In S4, the solvent includes one or more of methanol, ethanol, and isopropanol; the acid used is one or more of hydrochloric acid, oxalic acid, and acetic acid.

5. The method for preparing the transparent, flexible, and antifouling coating according to claim 1, characterized in that: In S5, the solvent includes one or more of methanol, ethanol, and isopropanol.

6. The method for preparing the transparent, flexible, and antifouling coating according to claim 1, characterized in that: In S6, the solvent includes one or more of methanol, ethanol, and isopropanol.

7. The method for preparing the transparent, flexible, and antifouling coating according to claim 1, characterized in that: In S7, the solvent includes one or more of methanol, ethanol, and isopropanol.

8. The method for preparing the transparent, flexible, and antifouling coating according to claim 1, characterized in that: In S8, the coating method includes one or more of brush coating, scraping coating, spraying, spin coating, drip coating, and dip coating; the substrate includes one of steel sheet, glass sheet, ceramic sheet, polymethyl methacrylate sheet, polycarbonate sheet, and polyethylene terephthalate sheet; the substrate standing temperature is 20-80℃; and the substrate standing time is more than 0.5h.

9. A transparent, flexible, and stain-resistant coating, characterized in that... It is prepared by the preparation method described in claims 1-8.

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