A method for preparing an organic / inorganic composite coating layer having transparency, ultraviolet resistance, and stain resistance

Abstract

The application discloses a preparation method of an organic / inorganic composite coating with transparency, ultraviolet resistance and antifouling property, and comprises the following steps: step one, preparing SiO2 by adopting an acid catalysis sol-gel method; and step two, preparing the organic / inorganic hybrid antifouling coating with high hardness, transparency and ultraviolet resistance by graft polymerization. The method prepares SiO2 by the sol-gel method, constructs a continuous silicone resin network by using methylphenyl polysiloxane resin, simultaneously adds SiO2 of the inorganic phase and MT-PDMS and octocrylene of the organic phase as polymerization reactants, and prepares the organic / inorganic hybrid coating through grafting and polymerization. The unique design makes the coating have excellent transparency, antifouling property and ultraviolet resistance. In addition, the coating also has good hardness and friction resistance, and still maintains excellent transparency and ultraviolet resistance in low-temperature and high-temperature environments.

Description

Technical Field

[0001] This invention relates to a method for preparing an organic / inorganic composite coating, specifically a method for preparing an organic / inorganic composite coating with transparency, UV resistance, and stain resistance. Background Technology

[0002] Antifouling coatings, also known as antifouling paints or antifouling coatings, are functional coatings with low surface energy, making it difficult for water-based and oil-based contaminants to adhere to their surfaces. Due to their anti-fouling and self-cleaning properties, antifouling coatings are widely used in smart glass, photovoltaic devices, ship antifouling and corrosion protection, and pipeline drag reduction. Generally, antifouling coatings are classified according to their chemical composition into two main types: inorganic coatings and organic coatings. Inorganic coatings are mainly composed of metal oxides (SiO2, Al2O3), silicates, or ceramics (SiC, TiN), forming a network structure through ionic / covalent bonds. Inorganic coatings have advantages such as high hardness, good wear resistance, and good mechanical properties, but also disadvantages such as high brittleness and susceptibility to cracking. Organic coatings, on the other hand, use polymers as a matrix (epoxy resins, polyurethanes, acrylates, etc.), often containing C / C / CO covalent bonds and van der Waals forces, exhibiting good crosslinking density and flexibility, but their hardness and mechanical properties are far inferior to inorganic coatings.

[0003] To address the aforementioned issues, organic / inorganic hybrid coatings have become a research hotspot in recent years. These coatings combine the advantages of inorganic phases (SiO2, ZnO, etc.) with organic phases (silicone resins, polyurethanes, etc.) and are prepared through molecular-level interface design and chemical bonding. This preparation method breaks down the performance barriers between inorganic and organic phases and is considered a solution to the problems described.

[0004] Meanwhile, with industrial progress and consumption upgrades, the performance requirements for antifouling coatings are becoming increasingly stringent. Single-function coatings can no longer meet the extreme pursuit of material performance by modern industries and consumer products. Multifunctional protective coatings can organically integrate multiple protective mechanisms (physical shielding, chemical stabilization, surface energy regulation, etc.) into a synergistic coating system through material innovation and process optimization, which has become an inevitable trend in the field of antifouling coating technology. Therefore, developing an organic / inorganic composite coating preparation method that can effectively synergistically combine UV protection and antifouling functions, while also possessing good durability, environmental friendliness, and process feasibility, not only has significant scientific and technological value but also broad commercial application prospects.

[0005] The team led by Lü Jianyong at the Institute of Chemistry, Chinese Academy of Sciences (Guo X, Di Y, Liang Q, et al. Inorganic–organic silica / PDMS nanocomposite antiadhesive coating with ultrahighhardness and thermal stability[J]. ACS Applied Materials & Interfaces, 2023,15 (13): 17245-17255.) proposed a silica / polydimethylsiloxane (PDMS) nanocomposite coating (SPNC). This coating, achieved through a sol-gel method and covalent bonding, covalently embeds nanophase PDMS as a dispersed phase into the continuous silica phase. The nano-confined PDMS phase exhibits enhanced thermal stability and imparts a smooth behavior to the SPNC; simultaneously, the enrichment of PDMS on the surface reveals a gradient composition of the coating. The obtained SPNC coating simultaneously possesses a high nanoindentation hardness of 3.07 GPa and a pencil hardness exceeding 9H, a thermal stability of up to 400°C, and excellent adhesion strength to various substrates. In addition, SPNC also features high optical transparency, good flexibility, and resistance to bacterial adhesion and chemical corrosion.

[0006] A team led by Chen R, Zhang Y, Xie Q, et al. Transparent polymer‐ceramic hybrid antifouling coating with superior mechanical properties[J]. Advanced Functional Materials, 2021, 31 (19): 2011145. at South China University of Technology successfully prepared an organic / inorganic hybrid waterborne antifouling coating by compositing amine-terminated hyperbranched polysiloxane with stain-resistant zirconium oxide particles. The amine-terminated hyperbranched polysiloxane was prepared from amine-functionalized silane, while the stain-resistant zirconium oxide particles were obtained by reacting zirconium oxide with epoxy-functionalized silane and zwitterionic silane. This composite coating exhibits a combination of polymer and ceramic properties, possessing not only high transparency, high hardness, and excellent substrate adhesion, but also good flexibility. Furthermore, the introduction of zwitterionic groups gives the coating significant oil repellency and scale resistance. This organic / inorganic hybrid waterborne antifouling coating offers significant advantages for the development of foldable displays, optical sensors, and biomedical facilities.

[0007] The team led by Guo Zhiguang at Hubei University (Guo M, Zhang S, Zhang H, et al. Organic–inorganic hybridisation strategy for synthesizing durable colored superamphiphobic coatings[J]. Materials Horizons, 2025, 12(10): 3378-3387.) successfully prepared colored superamphiphobic coatings based on an organic-inorganic hybrid strategy. This involved physically grinding metakaolin, nano-silica, and organic dyes with fluorosilanes, followed by spraying the resulting powder onto various substrate surfaces. After curing, the powder was successfully prepared. This method, by controlling the mass ratio of MK to SiO2, grinds the powder into a cauliflower-like micro / nano cluster structure, thereby forming a stable air cushion at the solid-liquid interface. This organic / inorganic hybrid coating exhibits excellent durability, high color fastness, and superior self-cleaning and anti-fouling properties. Even after 150 days of outdoor exposure, it retains its color and superamphiphobic characteristics, showing broad application prospects in heritage restoration and mural conservation.

[0008] However, while these coatings improve mechanical properties or flexibility, they do not simultaneously achieve the desired multi-functionality, such as transparency, hardness, stain resistance, and UV resistance, further limiting their application in fields like glass and construction. Therefore, designing organic / inorganic hybrid coatings with high hardness, transparency, UV resistance, and stain resistance remains a challenging task. Summary of the Invention

[0009] This invention provides a method for preparing an organic / inorganic composite coating with transparency, UV resistance, and stain resistance. The method involves preparing silica (SiO2) via a sol-gel method, constructing a continuous organosilicon resin network using methylphenyl polysiloxane resin (MPSR), and simultaneously adding inorganic SiO2 and organic methoxy-polydimethylsiloxane (MT-PDMS) and 2-cyano-3,3-diphenylacrylate-2-ethylhexyl ester (octocrylene) as polymerization reactants. The organic / inorganic hybrid coating is then prepared through grafting and polymerization. This unique design results in a coating with excellent transparency, stain resistance, and UV resistance. Furthermore, the coating exhibits good hardness and abrasion resistance, and maintains excellent transparency and UV resistance even at low and high temperatures.

[0010] The objective of this invention is achieved through the following technical solution:

[0011] A method for preparing an organic / inorganic composite coating with transparency, UV resistance, and stain resistance, such as... Figure 1 As shown, it includes the following steps:

[0012] Step 1: Prepare SiO2 using the acid-catalyzed sol-gel method;

[0013] Step 2: Prepare a high-hardness, transparent, and UV-resistant organic / inorganic hybrid antifouling coating (UV-HSC) via graft polymerization:

[0014] Step 2: Disperse SiO2 uniformly in a solvent to obtain a SiO2 dispersion. The SiO2 content in the SiO2 dispersion is 1.0~6.0 wt%, and the solvent is xylene, toluene, or cyclohexanone.

[0015] Step 2: Add octocrylene to the SiO2 dispersion and disperse it evenly to obtain mixed solution A. The content of octocrylene in mixed solution A is 0.5~5 wt%.

[0016] Steps 2 and 3: Add MT-PDMS and MPSR to mixed solution A and disperse them evenly to obtain mixed solution B. The content of MT-PDMS in mixed solution B is 1.0~6.0 wt%, and the content of MPSR is 40~60 wt%.

[0017] Step 24: Spray the mixed solution B onto a clean substrate (glass, plastic, or metal substrate), controlling the spray diameter to be 0.2~0.5 mm, the spray pressure to be 1.0~2.0 bar, and the coating thickness to be 30~60µm;

[0018] Step 25: Cover the sample that has been sprayed in Step 24 and allow it to dry at room temperature for 0.5 to 1.5 hours to allow some of the solvent to evaporate;

[0019] Step 26: Cur the sample from Step 25 in a forced-air drying oven at 150~200℃ for 0.5~1.5 hours;

[0020] Step 27: Remove the sample from the drying oven and cool it to room temperature (25°C) to obtain UV-HSC.

[0021] Compared with the prior art, the present invention has the following advantages:

[0022] 1. Silica, as a rigid filler, is uniformly dispersed in an organosilicon network (MPSR). This not only controls surface roughness but also provides mechanical strength to the coating, resulting in a coating with good hardness and wear resistance. Furthermore, silica acts as an anchoring material for MT-PDMS; by grafting MT-PDMS, a low-surface-energy polymer, the coating exhibits excellent anti-fouling properties.

[0023] 2. Continuous methylphenyl polysiloxane resin (MPSR) can be used to construct an organosilicon resin network. By adding inorganic phase SiO2 and organic methoxy-polydimethylsiloxane (MT-PDMS), a novel organic / inorganic hybrid structure can be constructed.

[0024] 3. Silica particles scatter ultraviolet light, which can reduce the depth of ultraviolet light incidence; octocrylene absorbs ultraviolet light energy through molecular absorption, and the two form a dual protection system of "physical barrier + chemical absorption". Attached Figure Description

[0025] Figure 1 The flowchart and reaction principle diagram for the preparation of UV-HSC are shown.

[0026] Figure 2 A comparison chart of stain resistance tests on bare glass and glass coated with UV-HSC, including tests on water, juice, beer, sparkling beverages, milk, and vegetable oil.

[0027] Figure 3 A stain resistance test diagram for bare glass and an oil-based pen coated with UV-HSC;

[0028] Figure 4 Comparison of stain resistance tests between bare glass and glass coated with UV-HSC. The tests included the stain resistance performance against common contaminants on glass: juice, ink, artificial rain, and artificial snow.

[0029] Figure 5 UV performance test charts were obtained for bare glass, coating without octocrylene (HSC), and UV-HSC.

[0030] Figure 6 Visible light transmittance test charts were obtained for bare glass, coating without octocrylene (HSC), and UV-HSC.

[0031] Figure 7 This is a graph from a UV-HSC hardness test.

[0032] Figure 8 SEM and EDS test images of UV-HSC;

[0033] Figure 9 The infrared spectrum of UV-HSC;

[0034] Figure 10 TGA, DTA, and DSC test graphs for UV-HSC

[0035] Figure 11 This is an XPS test graph for UV-HSC. Detailed Implementation

[0036] The technical solution of the present invention will be further described below with reference to the embodiments, but it is not limited thereto. Any modifications or equivalent substitutions to the technical solution of the present invention without departing from the spirit and scope of the technical solution of the present invention should be covered within the protection scope of the present invention.

[0037] Example 1:

[0038] (1) Preparation of SiO2 by acid-catalyzed sol-gel method. 0.5 g of tetraethyl orthosilicate was dissolved in 5 g of anhydrous ethanol solution, followed by the addition of 0.25 g of glacial acetic acid. The solution was hydrolyzed by glacial acetic acid and stirred at room temperature (25 °C) for 12 hours. The silica sol was then aged at room temperature (25 °C) for 75 hours. After aging, the silica sol was transferred to a forced-air drying oven and dried at 85 °C for 12 hours to obtain SiO2 powder. Finally, the dried SiO2 powder was ground thoroughly in a mortar and screened using a 300-mesh sieve to remove particles that did not meet the particle size requirements.

[0039] (2) Preparation of a high-hardness, transparent, and UV-resistant organic / inorganic hybrid antifouling coating (UV-HSC) by graft polymerization. First, 0.05 g of sieved SiO2 was uniformly dispersed in 2 ml of xylene solvent by ultrasonication (30 kHz, 10 min) and stirring (1500 r / min). Next, 0.05 g of octocrylene was added to the above solution, and stirring was continued for 0.5 hours (1500 r / min) to ensure uniform dispersion. Then, 0.05 g of MT-PDMS and 10 ml of MPSR were added to the solution, and stirring was continued at 1500 r / min for 4.0 hours at room temperature.

[0040] (3) The prepared coating was sprayed onto a clean glass substrate with a spray diameter of 0.3 mm and a spray pressure of 1.2 bar, and the coating thickness was controlled to be 30 µm. The sprayed sample was then covered and dried at room temperature for 1 hour to allow partial solvent evaporation. Finally, it was cured in a forced-air drying oven at 180 °C for 1 hour. After curing, the sample was removed from the forced-air drying oven and cooled to room temperature (25 °C) to obtain UV-HSC.

[0041] Example 2:

[0042] (1) Preparation of SiO2 by acid-catalyzed sol-gel method. 0.5 g of tetraethyl orthosilicate was dissolved in 5 g of anhydrous ethanol solution, followed by the addition of 0.25 g of glacial acetic acid. The solution was hydrolyzed by glacial acetic acid and stirred at room temperature (25 °C) for 12 hours. The silica sol was then aged at room temperature (25 °C) for 75 hours. After aging, the silica sol was transferred to a forced-air drying oven and dried at 80 °C for 12 hours to obtain SiO2 powder. Finally, the dried SiO2 powder was ground thoroughly in a mortar and screened using a 300-mesh sieve to remove particles that did not meet the particle size requirements.

[0043] (2) Preparation of a high-hardness, transparent, and UV-resistant organic / inorganic hybrid antifouling coating (UV-HSC) by graft polymerization. First, 0.1 g of sieved SiO2 was uniformly dispersed in 2 ml of xylene solvent by ultrasonication (30 kHz, 10 min) and stirring (1500 r / min). Next, 0.05 g of octocrylene was added to the above solution, and stirring was continued for 0.5 hours (1500 r / min) to ensure uniform dispersion. Then, 0.05 g of MT-PDMS and 10 ml of MPSR were added to the solution, and stirring was continued at 1500 r / min for 4.0 hours at room temperature.

[0044] (3) The prepared coating was sprayed onto a clean glass substrate with a spray diameter of 0.3 mm and a spray pressure of 1.2 bar, and the coating thickness was controlled to be 30 µm. The sprayed sample was then covered and dried at room temperature for 1 hour to allow partial solvent evaporation. Finally, it was cured in a forced-air drying oven at 180 °C for 1 hour. After curing, the sample was removed from the forced-air drying oven and cooled to room temperature (25 °C) to obtain UV-HSC.

[0045] Example 3:

[0046] (1) Preparation of SiO2 by acid-catalyzed sol-gel method. 0.5 g of tetraethyl orthosilicate was dissolved in 5 g of anhydrous ethanol solution, followed by the addition of 0.25 g of glacial acetic acid. The solution was hydrolyzed by glacial acetic acid and stirred at room temperature (25 °C) for 12 hours. The silica sol was then aged at room temperature (25 °C) for 75 hours. After aging, the silica sol was transferred to a forced-air drying oven and dried at 90 °C for 12 hours to obtain SiO2 powder. Finally, the dried SiO2 powder was ground thoroughly in a mortar and screened using a 300-mesh sieve to remove particles that did not meet the particle size requirements.

[0047] (2) Preparation of a high-hardness, transparent, and UV-resistant organic / inorganic hybrid antifouling coating (UV-HSC) by graft polymerization. First, 0.1 g of sieved SiO2 was uniformly dispersed in 2 ml of xylene solvent by ultrasonication (30 kHz, 10 min) and stirring (1500 r / min). Next, 0.1 g of octocrylene was added to the above solution, and stirring was continued for 0.5 hours (1500 r / min) to ensure uniform dispersion. Then, 0.15 g of MT-PDMS and 10 ml of MPSR were added to the solution, and stirring was continued at 1500 r / min for 4.0 hours at room temperature.

[0048] (3) The prepared coating was sprayed onto a clean glass substrate with a spray diameter of 0.3 mm and a spray pressure of 1.2 bar, and the coating thickness was controlled to be 40 µm. The sprayed sample was then covered and dried at room temperature for 1 hour to allow partial solvent evaporation. Finally, it was cured in a forced-air drying oven at 180°C for 1 hour. After curing, the sample was removed from the forced-air drying oven and cooled to room temperature (25°C) to obtain UV-HSC.

[0049] Example 4:

[0050] (1) Preparation of SiO2 by acid-catalyzed sol-gel method. 0.5 g of tetraethyl orthosilicate was dissolved in 5 g of anhydrous ethanol solution, followed by the addition of 0.25 g of glacial acetic acid. The solution was hydrolyzed by glacial acetic acid and stirred at room temperature (25 °C) for 12 hours. The silica sol was then aged at room temperature (25 °C) for 75 hours. After aging, the silica sol was transferred to a forced-air drying oven and dried at 90 °C for 12 hours to obtain SiO2 powder. Finally, the dried SiO2 powder was ground thoroughly in a mortar and screened using a 300-mesh sieve to remove particles that did not meet the particle size requirements.

[0051] (2) Preparation of a high-hardness, transparent, and UV-resistant organic / inorganic hybrid antifouling coating (UV-HSC) by graft polymerization. First, 0.1 g of sieved SiO2 was uniformly dispersed in 2 ml of xylene solvent by ultrasonication (30 kHz, 10 min) and stirring (1500 r / min). Next, 0.2 g of octocrylene was added to the above solution, and stirring was continued for 0.5 hours (1500 r / min) to ensure uniform dispersion. Then, 0.15 g of MT-PDMS and 10 ml of MPSR were added to the solution, and stirring was continued at 1500 r / min for 4.0 hours at room temperature.

[0052] (3) The prepared coating was sprayed onto a clean glass substrate with a spray diameter of 0.3 mm and a spray pressure of 1.2 bar, and the coating thickness was controlled to be 40 µm. The sprayed sample was then covered and dried at room temperature for 1 hour to allow partial solvent evaporation. Finally, it was cured in a forced-air drying oven at 180 °C for 1 hour. After curing, the sample was removed from the forced-air drying oven and cooled to room temperature (25 °C) to obtain UV-HSC.

[0053] Example 5:

[0054] (1) Preparation of SiO2 by acid-catalyzed sol-gel method. 0.5 g of tetraethyl orthosilicate was dissolved in 5 g of anhydrous ethanol solution, followed by the addition of 0.25 g of glacial acetic acid. The solution was hydrolyzed by glacial acetic acid and stirred at room temperature (25 °C) for 12 hours. The silica sol was then aged at room temperature (25 °C) for 75 hours. After aging, the silica sol was transferred to a forced-air drying oven and dried at 85 °C for 12 hours to obtain SiO2 powder. Finally, the dried SiO2 powder was ground thoroughly in a mortar and screened using a 300-mesh sieve to remove particles that did not meet the particle size requirements.

[0055] (2) Preparation of a high-hardness, transparent, and UV-resistant organic / inorganic hybrid antifouling coating (UV-HSC) by graft polymerization. First, 0.1 g of sieved SiO2 was uniformly dispersed in 2 ml of xylene solvent by ultrasonication (30 kHz, 10 min) and stirring (1500 r / min). Next, 0.3 g of octocrylene was added to the above solution, and stirring was continued for 0.5 hours (1500 r / min) to ensure uniform dispersion. Then, 0.15 g of MT-PDMS and 10 ml of MPSR were added to the solution, and stirring was continued at 1500 r / min for 4.0 hours at room temperature.

[0056] (3) The prepared coating was sprayed onto a clean glass substrate with a spray diameter of 0.3 mm and a spray pressure of 1.2 bar, and the coating thickness was controlled to be 30 µm. The sprayed sample was then covered and dried at room temperature for 1 hour to allow partial solvent evaporation. Finally, it was cured in a forced-air drying oven at 180°C for 1 hour. After curing, the sample was removed from the forced-air drying oven and cooled to room temperature (25°C) to obtain UV-HSC.

[0057] Example 6:

[0058] This embodiment tested the performance of the antifouling coating (UV-HSC) prepared in Example 5, and the test results are as follows:

[0059] 1. Antifouling performance test

[0060] Liquid repellency is a recognized and fundamental method for testing the antifouling properties of coatings. It is evaluated by measuring the water contact angle (WCA) and sliding angle (WSA) on the coating surface. In Example 5, the coating's water contact angle and sliding angle were 109.6° and 2.7°, respectively.

[0061] To demonstrate the coating's antifouling properties against various liquids, including water, sparkling beverages, juice, and milk, a sliding test was conducted. The results are as follows: Figure 2 As shown, the tilt angle of the glass is 30°. It is obvious that they would be difficult to slide on bare glass, but they can slide easily on coated glass surfaces.

[0062] The stain-repellent properties of UV-HSC extend beyond its ability to repel liquids with the aforementioned surface tension. Further testing and research are needed to address common stains such as oil-based pens, rainwater, and snow. Therefore, the stain-repellent effect of UV-HSC on oil-based pens was further tested, and the results are as follows: Figure 3 As shown. Writing with an oil-based pen on bare glass and glass coated with UV-HSC was impossible on bare glass, but the writing on the UV-HSC coated glass was easily erased.

[0063] Simultaneously, the sliding effects of juice, ink, artificial rain, and artificial snow were further tested on bare glass and glass coated with UV-HSC. The glass slide was tilted at 30°, and the liquid dripping angle was 90° to the vertical plane. The results are as follows. Figure 4 As shown, juice, ink, artificial rain, and artificial snow are difficult to slide off bare glass, exhibiting a very noticeable trailing effect. However, on glass coated with UV-HSC, juice, ink, artificial rain, and artificial snow slide off easily, leaving almost no residue on the glass surface and without any trailing effect.

[0064] 2. UV resistance and transparency test

[0065] The UV resistance of UV-HSC depends on two aspects. Firstly, silica particles have a certain scattering effect on ultraviolet light, often used to reduce the depth of ultraviolet light incidence. Secondly, octocrylene is a substance with good ultraviolet absorption properties. Through its conjugated double bond structure (-C=C-COO-), it can absorb UVB (280~320nm) and part of UVA (320~400 nm), i.e., (280~365nm). Simply put, it can convert light energy into heat energy or low-energy radiation through electronic transitions, preventing ultraviolet light from directly damaging the coating polymer chains or substrate. With the combined action of SiO2 and octocrylene, a dual protection system of "physical barrier + chemical absorption" can be formed.

[0066] Based on this, ultraviolet performance tests were conducted on bare glass, coating without octocrylene (HSC), and UV-HSC, and the results are as follows: Figure 5 As shown, bare glass has extremely low absorption of ultraviolet light, and the effect of the coating without octocrylene (HSC) is not very significant. However, the coating combining SiO2 and octocrylene (UV-HSC) has a very high absorption rate of ultraviolet light in the 280~365nm range.

[0067] Simultaneously, visible light transmittance tests were conducted on the transparency of bare glass, HSC, and UV-HSC, and the results are as follows: Figure 6 As shown, UV-HSC has a visible light transmittance of up to 95.1%, clearly demonstrating its excellent transparency, and the coating does not affect the transparency of the glass.

[0068] 3. Hardness test of the coating

[0069] The mechanical properties of the coating are considered a critical performance factor in practical applications, especially for coatings on glass substrates, as they determine its service life. The highly cross-linked MPSR and rigid SiO2 endow the coating with excellent mechanical properties. Pencil hardness testing (international standard ASTM D3363) was performed using UV-HSC, with each pencil being tested three times. Figure 7 As can be seen, under the addition amount and reaction conditions of Example 5, the hardness of the coated pencil reached 8H.

[0070] 4. Field emission scanning electron microscopy (FE-SEM) and energy-dispersive spectroscopy (EDS) testing

[0071] pass Figure 8 The SEM images show a uniform and smooth coating surface with good film formation, and no fine cracks or bubbles appeared during the curing process. Furthermore... Figure 8 The EDS image also shows that the elements on the coating surface are evenly distributed.

[0072] 5. Fourier Transform Infrared (FTIR) Test

[0073] Fourier transform infrared spectroscopy (FTIR) confirmed the changes in the functional groups during the coating preparation process. The synthesis processes of SiO2, MPSR, MT-PDMS, octocrylene, and UV-HSC were analyzed by FTIR, and the results are as follows: Figure 9 As shown. SiO2 at 3400~3200 cm⁻¹ -1 A broad peak of free -OH is present at 950 cm⁻¹. -1 There is bending vibration of OH at that location. Simultaneously, at 2840 cm⁻¹... -1The absorption peak at 1700 cm⁻¹ belongs to the -CHO stretching vibration in MT-PDMS. However, these peaks disappear in UV-HSC, indicating that the hydroxyl and methoxy groups have undergone a condensation reaction and been consumed. Therefore, it can be demonstrated that the silanol groups (Si-OH) on the SiO₂ surface can undergo interfacial condensation with MPSR to form Si-O bonds, and can also undergo a methanol removal condensation reaction with the methoxy group (-OCH₃) of MT-PDMS to form Si-O bonds. The carbonyl group (C=O) of octocrylene at 1700 cm⁻¹... -1 The characteristic peak at the point of origin also reappears in situ in UV-HSC without shift. This indicates that octocrylene is successfully retained in the coating through physical embedding and weak bonds (such as hydrogen bonds).

[0074] 6. Thermogravimetric analysis (TGA), differential thermal analysis (DTA), and differential scanning calorimetry (DSC)

[0075] pass Figure 10 The TGA, DTG, and DSC tests shown confirm that UV-HSC exhibits good thermal stability. The coating experiences slight weight loss and endothermic reaction around 100°C, due to the evaporation of residual solvents, which does not damage the coating structure. Starting at 300°C, a small amount of low-molecular-weight components slowly decompose; the dramatic exothermic reaction and significant weight loss at 550°C indicate the breakdown of the coating's main chain, i.e., its network structure. Overall, the coating demonstrates good high-temperature resistance and is suitable for applications in glass, construction, and other fields.

[0076] 7. X-ray photoelectron spectroscopy (XPS)

[0077] pass Figure 11 The XPS test results show the chemical composition of the UV-HSC prepared and the chemical state of its elements, further proving the successful conduct of the reaction.

Claims

1. A method for preparing an organic / inorganic composite coating with transparency, UV resistance, and stain resistance, characterized in that... The method includes the following steps: Step 1: Prepare SiO2 using the acid-catalyzed sol-gel method; Step 2: Prepare a high-hardness, transparent, and UV-resistant organic / inorganic hybrid antifouling coating through graft polymerization: Step 2:

1. Disperse SiO2 uniformly in a solvent to obtain a SiO2 dispersion, wherein the SiO2 content in the dispersion is 1.0~6.0 wt%. Step 2: Add octocrylene to the SiO2 dispersion and disperse it evenly to obtain mixed solution A. The content of octocrylene in mixed solution A is 0.5~5 wt%. Steps 2 and 3: Add methoxy-polydimethylsiloxane and methylphenyl polysiloxane resin to mixed solution A and disperse them evenly to obtain mixed solution B. The content of methoxy-polydimethylsiloxane in mixed solution B is 1.0~6.0 wt%, and the content of methylphenyl polysiloxane resin is 40~60 wt%. Step 24: Spray the mixed solution B onto a clean substrate; Step 25: Cover and dry the sample after spraying in Step 24 at room temperature to allow some of the solvent to evaporate; Step 26: Cur the sample from Step 25 in a drying oven; Step 27: Remove the sample from the drying oven and cool it to room temperature to obtain UV-HSC.

2. The method for preparing the organic / inorganic composite coating with transparency, UV resistance and antifouling properties according to claim 1, characterized in that... In step two, the solvent is xylene, toluene, or cyclohexanone.

3. The method for preparing the organic / inorganic composite coating with transparency, UV resistance, and antifouling properties according to claim 1, characterized in that... In steps two and four, the substrate is glass, plastic, or metal.

4. The method for preparing the organic / inorganic composite coating with transparency, UV resistance, and antifouling properties according to claim 1, characterized in that... In steps two and four, the spraying diameter is controlled to be 0.2~0.5 mm, the spraying pressure to be 1.0~2.0 bar, and the coating thickness to be 30~60µm.

5. The method for preparing the organic / inorganic composite coating with transparency, UV resistance and antifouling properties according to claim 1, characterized in that... In step two, the drying time is 0.5 to 1.5 hours.

6. The method for preparing the organic / inorganic composite coating with transparency, UV resistance and antifouling properties according to claim 1, characterized in that... In step two, the curing temperature is 150~200℃ and the time is 0.5~1.5 hours.

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