Preparation method and application of antifouling paint

Abstract

The invention discloses antifouling paint as well as a preparation method and application thereof, and belongs to the technical field of functional paint. The coating is prepared from a light-cured polyurethane prepolymer, modified silicon dioxide, a slow-release antifouling microcapsule and a low-surface-energy modifier. The preparation method comprises the following steps: synthesizing acrylated rosin dihydric alcohol, preparing a light-cured polyurethane prepolymer, mixing all the components, spraying, and carrying out ultraviolet curing. The obtained coating has super-hydrophobic, self-repairing and intelligent antifouling functions, is stable in performance in extreme environments such as salt mist, acid-base, ultraviolet aging and mechanical wear, and is suitable for marine equipment such as culture netting and ships. The invention solves the technical problems of toxic pollution and short service life of the traditional antifouling paint, and has obvious environmental friendliness and economic benefit.

Description

Technical Field

[0001] The present invention relates to the technical field of functional coatings, and in particular to a preparation method of an antifouling coating and application thereof. Background Art

[0002] Marine resources are the material foundation for sustainable development strategies in the 21st century. However, in the development of marine aquaculture resources, marine biofouling has severely hampered the development of the marine resource economy. The annual losses to local fisheries caused by marine biofouling are incalculable. Fish farming cages, after prolonged submersion in water, absorb fish excrement and waterborne contaminants, causing large numbers of filamentous algae, primarily Spirogyra, Diplocystis, and Algae, to form on the nets. The increase of these attachments not only hinders the smooth flow of water and the exchange of water bodies, but also easily causes the deterioration of water quality and lack of oxygen in the cage, affecting the growth of fish; the barnacles, oysters and other shellfish and algae attached to the cage system will increase the weight of the cage and reduce the buoyancy of the cage system; the large amount of algae and dirt growing on the cage become a place for pathogenic bacteria such as Aeromonas hydrophila and Vibrio marinum to grow and reproduce; at the same time, the seedlings are often entangled by filamentous algae such as Spirogyra and cannot escape, so they suffocate and die, and the emergence rate is greatly affected; it also reduces the activity ability of the fry, resulting in a decrease in the food intake of the fry, and large-scale diseases such as curvature will occur during the wintering period.

[0003] my country's marine cage aquaculture currently lacks effective and cost-effective methods for preventing fouling. Most net materials are inherently non-toxic and have a large surface area, which favors the growth of fouling organisms (including mites). The structure of the cage nets themselves also makes it difficult to clean attached marine organisms. Cleaning cage nets is expensive, and the process can cause varying degrees of damage to the nets, disrupting the life cycle of the aquacultured species and reducing the growth rate of cage-cultured fish.

[0004] Therefore, the prevention of fouling and biological contamination of aquaculture cages and the cleaning of cage nets are urgent problems that need to be solved in cage aquaculture. At present, there are mainly the following methods for cleaning deep-sea cages in China, including: (1) manual cleaning, which is effective but labor-intensive, time-consuming and labor-intensive; (2) biological removal, which is environmentally friendly and pollution-free, but not easy to implement; (3) mechanical cleaning, which is low in labor intensity and fast in speed, but inevitably causes damage to the nets; (4) drug cleaning, which is effective but can cause marine pollution; (5) using the sun exposure method. When the temperature is high in summer, half of the cage is exposed to the water surface and exposed to the sun. When the temperature is 37-38℃, the net is exposed for about 55 minutes, and when the temperature is 30-31℃, it is exposed for 90 minutes to kill the filamentous algae and other organisms attached to the cage; then switch to the other half of the cage for drying. Or, after replacing the cage with more attachments, put it in the sun to kill the attached organisms, and then beat it to remove them. However, it affects aquaculture production, and cages are prone to aging due to frequent exposure to the sun, so they should not be exposed to the sun frequently.

[0005] Based on this, the present application proposes a preparation method of an antifouling coating and its application to solve the above problems. Summary of the Invention

[0006] In view of the above content, it is necessary to provide a preparation method and application of antifouling coating. The antifouling coating prepared by this application is a composite coating with superhydrophobicity, self-repairing and high-efficiency antifouling properties, which is particularly suitable for harsh environments such as marine equipment and aquaculture nets.

[0007] In order to achieve the above object, the technical solution adopted by the present invention is:

[0008] An antifouling coating comprises the following components: 60-80 parts by weight of a photocurable polyurethane prepolymer, 1.5-3.0 parts by weight of modified silicon dioxide (M-SiO2), 5-10 parts by weight of sustained-release antifouling microcapsules, 0.5-2.0 parts by weight of a low surface energy modifier, and 0.5-1.5 parts by weight of a photoinitiator.

[0009] In the present invention, further, the antifouling coating includes the following components: photocurable polyurethane prepolymer: 70 parts by weight, modified silica (M-SiO2): 2.0 parts by weight, sustained-release antifouling microcapsules: 8 parts by weight, low surface energy modifier: 1.2 parts by weight, photoinitiator: 1.0 part by weight.

[0010] In the present invention, further, the light-curable polyurethane prepolymer is composed of acrylated rosin diol, isophorone diisocyanate and hydroxyethyl methacrylate, wherein the acrylated rosin diol accounts for 30-50% of the total mass of the prepolymer.

[0011] In the present invention, further, the acrylated rosin diol has a hydroxyl value of 200-220 mgKOH / g and is prepared by condensing dehydroabietic acid with acrylic acid and then esterifying with ethylene glycol.

[0012] In the present invention, further, the surface of the modified silica is grafted with methacryloxy groups via a silane coupling agent; the particle size of the modified silica is 20-50 nm, and the silane coupling agent is γ-methacryloxypropyltrimethoxysilane.

[0013] In the present invention, further, the wall material of the sustained-release antifouling microcapsule is polylactic acid, the sustained-release rate of the microcapsule in seawater with a pH of 7.5-8.5 is ≥72h, and the core material contains oleandrin and capsaicin; the mass ratio of the wall material to the core material is 1:0.5-2; the particle size of the sustained-release antifouling microcapsule is 1-5μm, the molecular weight of the wall material polylactic acid is 10,000-30,000Da, and the core material loading rate is 60-80%.

[0014] In the present invention, further, the low surface energy modifier is selected from perfluorooctyltriethoxysilane.

[0015] The present invention also provides a method for preparing the antifouling coating, which comprises the following steps:

[0016] (1) Synthesis of acrylic rosin diol: Dehydroabietic acid and acrylic acid are reacted in a molar ratio of 1:1.2-1.5, catalyzed by concentrated sulfuric acid, at 120°C for 2-3 hours, and the product is then esterified with ethylene glycol in a molar ratio of 1:2;

[0017] (2) Preparation of a photocurable polyurethane prepolymer: The acrylated rosin diol obtained in step (1) and isophorone diisocyanate were mixed at a -NCO / -OH molar ratio of 1.8-2.2, reacted at 75°C for 3 hours, hydroxyethyl methacrylate and a polymerization inhibitor were added, and reacted at 65°C until the -NCO disappeared;

[0018] (3) Construction of composite coating: prepolymer, M-SiO2, antifouling microcapsules, perfluorooctyl triethoxysilane and photoinitiator were mixed, ultrasonically dispersed and sprayed onto the substrate, pre-cured at 80 ° C for 5 min, and then heated at a wavelength of 365 nm and an energy of 500-800 mJ / cm 2 UV curing under conditions.

[0019] In the present invention, further, the UV curing is carried out under nitrogen protection, and the light intensity is 80-100mW / cm 2 .

[0020] The present invention also proposes an application of the above-mentioned antifouling coating in antifouling of marine equipment, which is applied to the surface of a substrate to form a coating, wherein the coating has a water contact angle greater than 160°, a scratch repair rate greater than or equal to 95%, and an impedance modulus value |Z| after immersion in a 3.5wt% NaCl solution for 28 days. 0.01 Hz>1×10 9 Ω·cm 2 .

[0021] In the present invention, further, the substrate is aquaculture nets, ship ballast tanks or ocean sensors, and the coating thickness is 50-100 μm.

[0022] The present invention has at least the following beneficial effects:

[0023] 1. Environmentally friendly antifouling mechanism: The antifouling coating of the present invention is used for marine antifouling, completely abandoning toxic antifouling agents such as organotin and copper compounds, and using natural antifouling active substances (oleandrin, capsaicin) to avoid marine ecological pollution; the intelligent controlled release of antifouling agents is achieved through microcapsule sustained-release technology, which significantly reduces the dosage and overcomes biological resistance. Among them, the micro-nano hierarchical rough structure (modified SiO2 covalent bonding) gives the coating superhydrophobicity (water contact angle > 160°), which physically blocks the attachment of marine organisms; the dynamic hydrogen bond network realizes the self-repair of coating scratches (repair rate ≥ 95%), and the function can be restored after wear and tear, extending the service life. In addition, the rigid tricyclic phenanthrene structure of rosin enhances the mechanical strength of the coating, resists water flow impact and mesh friction; covalently bonded SiO2 nanoparticles improve wear resistance, and it still remains superhydrophobic after being worn by sandpaper 1,000 times; it has excellent stability in acid and alkali resistance, UV resistance and high salt spray environment, and the antifouling performance attenuation in extreme environments is less than 5%.

[0024] 2. Multifunctional synergistic protection and efficiency enhancement: (1) Integrated anti-fouling and anti-corrosion: The super-hydrophobic barrier isolates the corrosive medium, and the microcapsules inhibit biological attachment, synergistically blocking the electrochemical corrosion path; (2) Improved anti-icing performance: The super-hydrophobic surface delays ice crystal nucleation, and the freezing time is extended to more than 700 seconds (-15℃), which is suitable for marine equipment in cold regions.

[0025] 3. Convenient construction and broad-spectrum applicability: The present invention also uses a UV curing process that is energy-saving and efficient (forming within 5 minutes), and is suitable for complex substrates such as nets, ships, and sensors. A thin coating of 50-100μm can achieve long-term protection, reducing coating costs and material consumption.

[0026] 4. Solve industry pain points: The method of the present invention breaks through the contradiction between "toxic pollution" and "short life" of traditional antifouling coatings, providing a sustainable marine protection solution; it overcomes the bottleneck of "poor mechanical stability" of superhydrophobic coatings, achieves functional regeneration through self-repair, and reduces maintenance frequency.

[0027] In summary, this invention integrates the three major technologies of rosin chemical modification, micro-nano covalent bonding and intelligent slow-release antifouling for the first time, achieving a synergistic breakthrough in superhydrophobicity, self-healing and long-term antifouling, realizing a synergistic leap in environmental protection, durability and functional integration, and providing a disruptive solution for the field of marine antifouling. DETAILED DESCRIPTION

[0028] All features disclosed in this specification, or all steps in the disclosed methods or processes, except mutually exclusive features and / or steps, can be combined in any manner.

[0029] Any feature disclosed in this specification (including any accompanying claims and abstract), unless otherwise stated, is merely one example of a series of equivalent or similar features.

[0030] Example 1:

[0031] This embodiment provides an antifouling coating, which includes the following components: 70 parts by weight of a photocurable polyurethane prepolymer, 2.0 parts by weight of modified silica (M-SiO2), 8 parts by weight of sustained-release antifouling microcapsules, 1.2 parts by weight of perfluorooctyltriethoxysilane, and 1.0 parts by weight of a photoinitiator TPO.

[0032] The photocurable polyurethane prepolymer is composed of acrylated rosin diol, isophorone diisocyanate, and hydroxyethyl methacrylate. The acrylated rosin diol accounts for 40% of the total prepolymer mass. The acrylated rosin diol has a hydroxyl value of 210 mgKOH / g and is produced by condensing dehydroabietic acid with acrylic acid, followed by esterification with ethylene glycol. The surface of the modified silica is grafted with methacryloxy groups via a silane coupling agent. The particle size of the modified silica is 30 nm, and the silane coupling agent is γ-methacryloyloxypropyltrimethoxysilane. The wall material of the sustained-release antifouling microcapsule is polylactic acid, the sustained-release rate of the microcapsule in seawater with a pH of 8.0 is ≥72h, and the core material contains oleandrin and capsaicin; the mass ratio of the wall material to the core material is 1:1.2; the particle size of the sustained-release antifouling microcapsule is 3μm, the molecular weight of the wall material polylactic acid is 20,000Da, and the core material loading rate is 70%.

[0033] The preparation method of the above antifouling coating is as follows:

[0034] (1) Synthesis of acrylated rosin diol (AR-diol): Dehydroabietic acid and acrylic acid were reacted in a molar ratio of 1:1.2, catalyzed by concentrated sulfuric acid, at 120°C for 3 h, and the product was then esterified with ethylene glycol in a molar ratio of 1:2.

[0035] (2) Preparation of a photocurable polyurethane prepolymer: The acrylated rosin diol obtained in step (1) and isophorone diisocyanate were mixed at a -NCO / -OH molar ratio of 2.0, reacted at 75°C for 3 h, hydroxyethyl methacrylate and a polymerization inhibitor were added, and reacted at 65°C until the -NCO disappeared;

[0036] (3) Construction of composite coating: prepolymer, M-SiO2, antifouling microcapsules, perfluorooctyl triethoxysilane and photoinitiator were mixed, ultrasonically dispersed and sprayed onto the substrate, pre-cured at 80 °C for 5 min, and then heated at a wavelength of 365 nm and an energy of 600 mJ / cm 2 The UV curing was carried out under nitrogen protection with a light intensity of 90 mW / cm 2 .

[0037] The antifouling effectiveness period of the coating in seawater environment is ≥24 months, and the barnacle attachment inhibition rate is >98%.

[0038] Example 2:

[0039] This embodiment provides an antifouling coating, which includes the following components: 60 parts by weight of a photocurable polyurethane prepolymer, 1.5 parts by weight of modified silica (M-SiO2), 5 parts by weight of sustained-release antifouling microcapsules, 1.0 parts by weight of perfluorooctyltriethoxysilane, and 1.5 parts by weight of a photoinitiator TPO.

[0040] The photocurable polyurethane prepolymer is composed of acrylated rosin diol, isophorone diisocyanate, and hydroxyethyl methacrylate, with the acrylated rosin diol comprising 30% of the total prepolymer mass. The acrylated rosin diol has a hydroxyl value of 200 mgKOH / g and is produced by condensing dehydroabietic acid with acrylic acid, followed by esterification with ethylene glycol. The surface of the modified silica is grafted with methacryloxy groups via a silane coupling agent; the particle size of the modified silica is 20 nm, and the silane coupling agent is γ-methacryloyloxypropyltrimethoxysilane. The wall material of the sustained-release antifouling microcapsule is polylactic acid, the sustained-release rate of the microcapsule in seawater with a pH of 8.5 is ≥72h, and the core material contains oleandrin and capsaicin; the mass ratio of the wall material to the core material is 1:0.5; the particle size of the sustained-release antifouling microcapsule is 1μm, the molecular weight of the wall material polylactic acid is 20,000Da, and the core material loading rate is 60%.

[0041] The preparation method of the above antifouling coating is as follows:

[0042] (1) Synthesis of acrylated rosin diol (AR-diol): Dehydroabietic acid and acrylic acid were reacted in a molar ratio of 1:1.4, catalyzed by concentrated sulfuric acid, at 120°C for 3 h, and the product was then esterified with ethylene glycol in a molar ratio of 1:2.

[0043] (2) Preparation of a photocurable polyurethane prepolymer: The acrylated rosin diol obtained in step (1) and isophorone diisocyanate were mixed at a -NCO / -OH molar ratio of 2.2, reacted at 75°C for 3 h, hydroxyethyl methacrylate and a polymerization inhibitor were added, and reacted at 65°C until the -NCO disappeared;

[0044] (3) Construction of composite coating: prepolymer, M-SiO2, antifouling microcapsules, perfluorooctyl triethoxysilane and photoinitiator were mixed, ultrasonically dispersed and sprayed onto the substrate, pre-cured at 80 °C for 5 min, and then heated at a wavelength of 365 nm and an energy of 800 mJ / cm 2 The UV curing was carried out under nitrogen protection with a light intensity of 80 mW / cm 2 .

[0045] The antifouling effectiveness period of the coating in seawater environment is ≥24 months, and the barnacle attachment inhibition rate is >98%.

[0046] Example 3:

[0047] This embodiment provides an antifouling coating, which includes the following components: 80 parts by weight of a photocurable polyurethane prepolymer, 3.0 parts by weight of modified silica (M-SiO2), 10 parts by weight of sustained-release antifouling microcapsules, 2.0 parts by weight of perfluorooctyltriethoxysilane, and 0.5 parts by weight of a photoinitiator TPO.

[0048] The photocurable polyurethane prepolymer is composed of acrylated rosin diol, isophorone diisocyanate, and hydroxyethyl methacrylate, with the acrylated rosin diol comprising 50% of the total prepolymer mass. The acrylated rosin diol has a hydroxyl value of 220 mgKOH / g and is produced by condensing dehydroabietic acid with acrylic acid, followed by esterification with ethylene glycol. The surface of the modified silica is grafted with methacryloxy groups via a silane coupling agent; the particle size of the modified silica is 50 nm, and the silane coupling agent is γ-methacryloyloxypropyltrimethoxysilane. The wall material of the sustained-release antifouling microcapsule is polylactic acid, the sustained-release rate of the microcapsule in seawater with a pH of 8.5 is ≥72 hours, and the core material contains oleandrin and capsaicin; the mass ratio of the wall material to the core material is 1:0.5; the particle size of the sustained-release antifouling microcapsule is 5 μm, the molecular weight of the wall material polylactic acid is 30,000 Da, and the core material loading rate is 80%.

[0049] The preparation method of the above antifouling coating is as follows:

[0050] (1) Synthesis of acrylated rosin diol (AR-diol): Dehydroabietic acid and acrylic acid were reacted in a molar ratio of 1:1.5, catalyzed by concentrated sulfuric acid, at 120°C for 3 h, and the product was then esterified with ethylene glycol in a molar ratio of 1:2.

[0051] (2) Preparation of a photocurable polyurethane prepolymer: The acrylated rosin diol obtained in step (1) and isophorone diisocyanate were mixed at a -NCO / -OH molar ratio of 2.2, reacted at 75°C for 3 h, hydroxyethyl methacrylate and a polymerization inhibitor were added, and reacted at 65°C until the -NCO disappeared;

[0052] (3) Construction of composite coating: prepolymer, M-SiO2, antifouling microcapsules, perfluorooctyl triethoxysilane and photoinitiator were mixed, ultrasonically dispersed and sprayed onto the substrate, pre-cured at 80 °C for 5 min, and then heated at a wavelength of 365 nm and an energy of 500 mJ / cm 2 The UV curing was carried out under nitrogen protection with a light intensity of 100 mW / cm 2 .

[0053] The antifouling effectiveness period of the coating in seawater environment is ≥24 months, and the barnacle attachment inhibition rate is >98%.

[0054] Comparative Example 1:

[0055] This comparative example provides an antifouling coating, wherein the raw materials thereof do not contain AR-diol but petroleum-based polyether diol is used instead. Except for this, the other methods are the same as those in Example 1.

[0056] Comparative Example 2:

[0057] This comparative example provides an antifouling coating, but removes M-SiO2 from the raw materials, and the other methods are the same as those in Example 1.

[0058] Comparative Example 3:

[0059] This comparative example provides an antifouling coating, in which the raw materials do not contain antifouling microcapsules, but oleandrin is directly added. Except for this, the other methods are the same as those in Example 1.

[0060] Comparative Example 4:

[0061] This comparative example provides an antifouling coating. In step (3), M-SiO2 is directly physically mixed (not UV-bonded). Apart from this, the other methods are the same as those in Example 1.

[0062] Comparative Example 5:

[0063] This comparative example provides an antifouling coating, except that the wall material of the antifouling microcapsule is replaced with gelatin (not polylactic acid), all other aspects are the same as those of Example 1.

[0064] Comparative Example 6:

[0065] This comparative example provides an anti-fouling means, which is an anti-fouling means in the prior art, specifically referring to Example 1 in CN105331168A.

[0066] Performance test results:

[0067] In order to verify the practical value of the antifouling coating of the present application, the applicant tested and compared the key performance data of the above embodiments and comparative examples, and all test data were taken as the average value ± standard deviation of three times.

[0068] Test 1:

[0069] This experiment tested the mechanical and self-repair properties of the following groups of antifouling coatings. The results are shown in Table 1:

[0070] Table 1 Comparison of mechanical and self-repairing performance

[0071]

[0072] Test results show that the lack of rosin rigidity (Comparative Example 1) leads to a 40% decrease in mechanical strength and a lack of self-healing ability. When M-SiO2 is not covalently bonded (Comparative Example 4), wear resistance deteriorates significantly (WCA↓28%), demonstrating that physical mixing cannot stabilize micro-nanostructures.

[0073] Test 2:

[0074] This experiment tests the antifouling and sustained-release properties of each group of antifouling coatings. To clearly verify the antifouling effect, all examples and comparative examples adopt a standardized coating process, as follows:

[0075] 1. Substrate treatment

[0076] The base material of the aquaculture net was a polyethylene monofilament woven net (pore size 2 cm), which was ultrasonically cleaned with acetone (20 min), degreased with alkaline solution (5% NaOH, 60°C) for 30 min, rinsed with deionized water, and dried at 80°C.

[0077] Metal substrate (tinplate): polished with 400-grit sandpaper to a surface roughness of Ra = 1.0 ± 0.2 μm, degreased with ethanol, and dried with nitrogen.

[0078] 2. Painting process

[0079] Spraying parameters: spray gun diameter: 1.2mm; air pressure: 0.4MPa; spraying distance: 20cm; coating thickness: 80±5μm (controlled by film thickness meter);

[0080] Curing process: Preheat substrate at 80°C for 5 minutes; spray coating evenly; level at 80°C for 5 minutes; UV curing: 365nm wavelength, light intensity 90mW / cm 2 , cumulative energy 600mJ / cm 2 (Nitrogen atmosphere).

[0081] 3. Antifouling performance test method

[0082] Actual sea hanging board test:

[0083] Location: Beihai aquaculture area, Guangxi (water temperature 25-30°C, salinity 3.2-3.5%);

[0084] Period: 90 days (July to October 2023, peak season for barnacle attachment);

[0085] Sample setup: 3 nets (20 cm × 20 cm) per group were fixed outside the deep-sea cage at a depth of 1 m.

[0086] Evaluation indicators:

[0087] (1) Barnacle attachment inhibition rate = (attachment amount of blank group - attachment amount of experimental group) / attachment amount of blank group × 100%;

[0088] (2) Biofilm coverage: the proportion of surface microbial film area observed by SEM;

[0089] (3) Antifouling agent residual rate: HPLC was used to detect the residual content of oleandrin in the coating.

[0090] 4. Sustained-release performance test method

[0091] Artificial seawater immersion experiment: Solution: pH 8.0 artificial seawater (ASTM D1141 standard), Condition: 30°C constant temperature shaking (120 rpm), Detection: Timed sampling, HPLC determination of the cumulative release rate of the antifouling agent.

[0092] The test results are shown in Table 2 (only a few sets of typical data are recorded):

[0093] Table 2 Comparison of antifouling and sustained-release performance

[0094] Group Barnacle attachment inhibition rate Antifouling agent residual rate Surface biofilm coverage Example 1 98.7％ 82.4％ ＜1％ Comparative Example 3 76.5％ 41.2％ 35％ Comparative Example 5 68.9％ 38.7％ 42％ Comparative Example 6 85.3％ — 18％

[0095] In addition, the applicant also compared the release rate of the microcapsule / gelatin wall material of Comparative Example 5 and Example 1 of the present application. The results are shown in Table 3:

[0096] Table 3 Release rate of microcapsules / gelatin wall materials

[0097]

[0098] Based on the above test results, it can be seen that the direct addition of the antifouling agent (Comparative Example 3) caused the antifouling rate to drop by 22.2% due to rapid dissolution; while the non-pH-responsive wall material (Comparative Example 5) released >98% within 72 hours, and the polylactic acid PLA microcapsules were able to achieve long-term sustained release; it can be seen that the synergistic mechanism of the present application: superhydrophobic surface (WCA>160°) reduces biological contact + microcapsule targeting can effectively inhibit larval attachment and achieve efficient antifouling.

[0099] The comprehensive performance of the present invention far exceeds that of the prior art. In the same test, the barnacle inhibition rate of comparative example 6 (CN105331168A) is ≤85.3% (98.7% of the present invention); it has no self-repair function and loses its anti-fouling function after wear; its salt spray resistance is only 500h (the impedance value of the present invention is kept>10 9 Ω·cm 2 , 28 days).

[0100] Test 3:

[0101] This test tests the stability under extreme environments, including:

[0102] 0.5mol / LHCl immersion for 7 days (simulating acid rain / industrial pollution), 0.5mol / LNaOH immersion for 7 days (simulating alkaline environment of biological mucus), UV aging for 500h (0.76W / m 2 @340nm, 60℃×500h)):

[0103] The stability of the coatings formed by the antifouling coatings of Example 1, Comparative Example 2, and Comparative Example 4 under the above extreme environment is compared, as shown in Table 4:

[0104] Table 4 Stability under extreme environments

[0105] Group 0.5M HCl soak for 7 days 0.5M NaOH soak for 7 days UV aging 500h WCA Retention Rate Antifouling retention rate WCA Retention Rate Example 1 98.0％ 95.8％ 96.7％ Comparative Example 2 75.3％ 71.6％ 68.4％ Comparative Example 4 63.2％ 60.1％ 57.9％

[0106] It can be seen that the covalently bonded M-SiO2 (Example 1) can effectively improve the acid and alkali resistance and the ultraviolet radiation aging resistance.

[0107] In summary, the antifouling coating of the present invention achieves the integrated functions of superhydrophobicity, self-repairing, and long-term antifouling through the collaborative design of rosin-modified polyurethane + covalently bonded SiO2 + intelligent sustained-release microcapsules. It still maintains excellent performance in extreme marine environments and has significant industrial application value.

[0108] The above-described embodiments merely illustrate several embodiments of the present invention, and while the descriptions are relatively specific and detailed, they should not be construed as limiting the scope of the present invention. It should be noted that a person skilled in the art would be able to make various modifications and improvements without departing from the spirit of the present invention, all of which fall within the scope of protection of the present invention. Therefore, the scope of protection of the present invention shall be determined by the appended claims.

Claims

1. An antifouling coating, characterized in that: The antifouling coating comprises the following components: 60-80 parts by weight of a photocurable polyurethane prepolymer, 1.5-3.0 parts by weight of modified silicon dioxide (M-SiO2), 5-10 parts by weight of a sustained-release antifouling microcapsule, 0.5-2.0 parts by weight of a low surface energy modifier, and 0.5-1.5 parts by weight of a photoinitiator.

2. The antifouling coating according to claim 1, characterized in that The light-curing polyurethane prepolymer consists of acrylated rosin diol, isophorone diisocyanate and hydroxyethyl methacrylate, wherein the acrylated rosin diol accounts for 30-50% of the total mass of the prepolymer.

3. The antifouling coating according to claim 2, characterized in that The acrylated rosin diol has a hydroxyl value of 200-220 mgKOH / g and is prepared by condensing dehydroabietic acid with acrylic acid and then esterifying with ethylene glycol.

4. The antifouling coating according to claim 1, characterized in that The surface of the modified silicon dioxide is grafted with methacryloxy groups via a silane coupling agent; the particle size of the modified silicon dioxide is 20-50 nm, and the silane coupling agent is gamma-methacryloxypropyltrimethoxysilane.

5. The antifouling coating according to claim 1, characterized in that The wall material of the sustained-release antifouling microcapsule is polylactic acid, the sustained-release rate of the microcapsule in seawater with a pH of 7.5-8.5 is ≥72h, and the core material contains oleandrin and capsaicin; the mass ratio of the wall material to the core material is 1:0.5-2; the particle size of the sustained-release antifouling microcapsule is 1-5μm, the molecular weight of the wall material polylactic acid is 10,000-30,000Da, and the core material loading rate is 60-80%.

6. The antifouling coating according to claim 1, characterized in that The low surface energy modifier is selected from perfluorooctyltriethoxysilane.

7. A method for preparing the antifouling coating according to any one of claims 1 to 6, characterized in that: The method comprises the following steps: (1) Synthesis of acrylic rosin diol: Dehydroabietic acid and acrylic acid are reacted in a molar ratio of 1:1.2-1.5, catalyzed by concentrated sulfuric acid, at 120°C for 2-3 hours, and the product is then esterified with ethylene glycol in a molar ratio of 1:2; (2) Preparation of a photocurable polyurethane prepolymer: The acrylated rosin diol obtained in step (1) and isophorone diisocyanate were mixed at a -NCO / -OH molar ratio of 1.8-2.2, reacted at 75°C for 3 hours, hydroxyethyl methacrylate and a polymerization inhibitor were added, and reacted at 65°C until the -NCO disappeared; (3) Construction of composite coating: prepolymer, M-SiO2, antifouling microcapsules, perfluorooctyl triethoxysilane and photoinitiator were mixed, ultrasonically dispersed and sprayed onto the substrate, pre-cured at 80 ° C for 5 min, and then heated at a wavelength of 365 nm and an energy of 500-800 mJ / cm 2 UV curing under conditions.

8. The method according to claim 7, characterized in that The UV curing is carried out under nitrogen protection, and the light intensity is 80-100 mW / cm 2 .

9. Use of the antifouling coating according to any one of claims 1 to 6 in antifouling of marine equipment, characterized in that: The coating is applied to the surface of the substrate, and its water contact angle is greater than 160°, the scratch repair rate is ≥95%, and the impedance modulus value |Z| after immersion in 3.5wt% NaCl solution for 28 days is 0.01 Hz>1×10 9 Ω·cm 2 .

10. The use according to claim 9, characterized in that The substrate is aquaculture nets, ship ballast tanks or ocean sensors, and the coating thickness is 50-100 μm.

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