Slow-release marine hull antifouling paint, preparation method and application thereof

Abstract

This invention provides a slow-release marine antifouling coating, its preparation method, and its application, belonging to the field of coating technology. The slow-release antifouling coating comprises 50-60 parts epoxy resin, 5-10 parts nano-cuprous oxide hollow spheres, 1-3 parts 7-amino-4-methylcoumarin, 3-5 parts quaternized chitosan, 2-4 parts DCOIT-supported mesoporous SiO2, 3-8 parts fluorosilane-modified SiO2, 0.5-2 parts carbon nanotubes, 5-10 parts polylactic acid microcapsules, and 1-3 parts silane coupling agent. Through the synergistic combination of epoxy resin, nano-cuprous oxide hollow spheres, and 7-amino-4-methylcoumarin, along with other raw materials, this invention prepares a marine antifouling coating with excellent antifouling performance, slow-release performance, adhesion performance, and environmental safety performance. It can effectively cope with the complex marine environment and has good application prospects.

Description

Technical Field

[0001] This invention relates to the field of coating technology, specifically to a slow-release marine antifouling coating, its preparation method, and its application. Background Technology

[0002] In the maritime transport and shipbuilding industries, marine biofouling has long been a key factor affecting ship performance and operating costs. With the continued growth of global trade, the efficient and safe operation of ships, as the primary carriers of maritime transport, is particularly important. However, when ships navigate in the marine environment, marine organisms such as barnacles, algae, and shellfish quickly attach and grow, forming a biofouling layer. This not only increases the ship's drag, leading to a significant increase in fuel consumption and operating costs, but can also affect the ship's speed and maneuverability, and even cause corrosion to the hull structure, shortening the ship's service life.

[0003] Traditional antifouling coatings primarily consist of organotin compounds, which inhibit marine organism attachment by continuously releasing toxic substances. However, these coatings pose a significant threat to the marine ecosystem, disrupting the marine food chain and leading to problems such as biodegradation and decreased reproductive capacity in marine organisms, severely threatening the marine ecological balance. With increasingly stringent environmental regulations, such as the International Convention on the Control of Harmful Antifouling Systems on Ships issued by the International Maritime Organization (IMO), the use of organotin-based antifouling coatings has been completely banned. This makes the development of environmentally friendly antifouling coatings an urgent need for the industry.

[0004] During long-term voyages, the antifouling coating of ships inevitably suffers damage. Traditional antifouling coating repair requires the ship to enter dry dock for complex pretreatment such as drying and sanding before recoating. This is not only time-consuming and labor-intensive, but also costly and causes the ship to be out of service, resulting in significant economic losses. While underwater repair technology can avoid dry docking, existing underwater adhesive antifouling coatings suffer from problems such as low bonding strength, slow curing speed, and unstable performance after contact with seawater, making efficient and reliable underwater repair difficult. Furthermore, current technology also has limitations regarding the durability of the antifouling performance of coatings. Most antifouling coatings cannot achieve controlled and slow release of the antifouling agent. Early release of the antifouling agent is too rapid, resulting in waste and potentially causing instantaneous high-concentration pollution to the environment; later release of the antifouling agent is insufficient, leading to a rapid decline in the antifouling effect, which fails to meet the antifouling requirements of ships during long-term voyages. Summary of the Invention

[0005] In view of the technical problems existing in the background art, the present invention provides a novel marine antifouling coating and its preparation method. The antifouling coating has excellent underwater adhesion performance, can achieve controlled and slow release of antifouling agent and is environmentally friendly. It has important practical significance and broad application prospects for solving the problem of biofouling on ships, reducing operating costs, protecting the marine ecological environment and promoting the sustainable development of the shipbuilding industry.

[0006] In a first aspect, the present invention provides a slow-release marine antifouling coating for ship hulls, the raw materials of which include the following: 50-60 parts epoxy resin, 5-10 parts nano-cuprous oxide (Cu2O) hollow spheres, 1-3 parts 7-amino-4-methylcoumarin (AMC), 3-5 parts quaternized chitosan, 2-4 parts DCOIT (4,5-dichloro-N-octyl-4-isothiazolin-3-one) supported mesoporous SiO2 (DCOIT@SiO2), 3-8 parts fluorosilane modified SiO2, 0.5-2 parts carbon nanotubes, 5-10 parts polylactic acid (PLA)@AMC microcapsules, and 1-3 parts silane coupling agent; by weight.

[0007] In the aforementioned slow-release marine antifouling coatings, the epoxy resin can be any one or a mixture of multiple types of bisphenol A epoxy resin, bisphenol F epoxy resin, linear phenolic epoxy resin (Novolac type), o-cresol epoxy resin, cyclohexane epoxy resin, vinylcyclohexene dioxide (VCD), isophorone diamine epoxy resin (IPDA type), triglycidylamine epoxy resin (such as TGA), polybutadiene epoxy resin, glycerol epoxy resin, brominated bisphenol A epoxy resin, chlorinated epoxy resin, furan epoxy resin, and silicone-containing epoxy resin.

[0008] This invention uses epoxy resin as the base material for antifouling coatings for ship hulls. It contains a large number of polar hydroxyl groups (-OH) and epoxy groups (-CH(O)CH-), which can form strong chemical bonds and physical adsorption with the surface of metal or composite ship hulls. Its adhesion is far superior to resins such as acrylic and polyurethane, ensuring that the coating is not easily peeled off under long-term seawater erosion and mechanical friction. Its durability is significantly better than traditional ship hull coatings such as asphalt-based and chlorinated rubber, reducing maintenance costs. After curing, the epoxy resin forms a dense three-dimensional cross-linked network, which can effectively block the penetration of seawater and various corrosive media within the seawater, delaying the electrochemical corrosion of the ship hull metal. The cured epoxy resin has extremely high hardness and impact resistance, able to withstand the impact of water flow, silt abrasion, and ice collisions suffered by the ship during navigation, effectively extending the coating's lifespan. Furthermore, epoxy resin is resistant to acids, alkalis, salts, and organic solvents, making it less prone to degradation or swelling in complex marine environments, maintaining the stability of the coating structure. Finally, epoxy resin itself is non-toxic, meeting the IMO's environmental requirements for antifouling coatings.

[0009] In the aforementioned slow-release marine antifouling coating, the nano-Cu2O hollow spheres possess a porous shell structure with a size of 50-300 nm and a shell thickness of 10-50 nm, exhibiting a pore size distribution of 5-25 nm. This invention uses nano-Cu2O hollow spheres as the primary antifouling agent in the hull antifouling coating. The hollow cavity of the nano-hollow spheres can serve as the antifouling agent (Cu2O). + The storage tank of nano-Cu2O, through adjusting the shell thickness and pore size, achieves controlled and slow release, avoiding initial burst release and later failure, extending the antifouling period to 3-5 years. The nano-size provides a larger specific surface area, allowing for more thorough contact between Cu2O and seawater. This larger specific surface area can improve antifouling efficiency by more than 30% compared to solid Cu2O particles per unit dosage. The Cu2O released by the nano-Cu2O hollow spheres... + It can interfere with the metabolic enzyme systems of algae, barnacles, and shellfish, inhibiting their larval attachment and growth, with a fouling resistance rate of ≥95%. The nano-Cu2O hollow spheres can also penetrate microbial cell membranes and bind to proteins / nucleic acids, exhibiting additional killing effects on bacteria and fungi, reducing biofilm formation. Its unique hollow structure reduces Cu through a slow-release mechanism. + The cumulative release rate meets the IMO Convention on the Control of Hazardous Prefouling Systems' limits on copper release rates. Compared to the banned tributyltin (TBT), nano-Cu2O exhibits significantly reduced toxicity to non-target organisms. Moreover, due to its unique hollow sphere structure, it exhibits low density, reducing coating weight while its rigid shell enhances the coating's compressive strength and abrasion resistance.

[0010] In the aforementioned slow-release marine antifouling coating, DCOIT@SiO2 specifically refers to a composite antifouling material in which DCOIT is fixed within the pores of mesoporous SiO2. The preferred particle size of the mesoporous SiO2 is 100-500 nm, and the pore size is 2-10 nm, to achieve high capacity loading and controlled slow release of the antifouling agent DCOIT. The preparation method of DCOIT@SiO2 is as follows: first, DCOIT is dissolved in a volatile solvent such as acetone; then, it is mixed with mesoporous SiO2 powder and continuously stirred to allow DCOIT molecules to be fully adsorbed into the mesoporous channels; subsequently, the solvent is evaporated and removed under ventilation conditions, fixing DCOIT inside the pores; and finally, it is obtained after washing and vacuum drying.

[0011] In the aforementioned slow-release marine antifouling coating, the fluorosilane-modified SiO2 has a particle size of 10-50 nm, which is used to construct a micro-nano rough structure in the coating and reduce surface energy, thereby synergistically enhancing the antifouling performance; the carbon nanotubes are preferably multi-walled carbon nanotubes with an outer diameter of 5-20 nm and a length of 1-20 μm, which are used to form a three-dimensional network structure and improve the mechanical strength, wear resistance and thermal conductivity of the coating.

[0012] In the aforementioned slow-release marine antifouling coatings, PLA@AMC microcapsules refer to slow-release microcapsules of PLA encapsulating AMC, with a size of 1-10 μm. The preparation method for PLA@AMC microcapsules can be as follows: hydrophobic PLA is dissolved in an organic solvent such as dichloromethane, while AMC is dispersed in the PLA solution as a core material; subsequently, under the action of an emulsifier, it is poured into an aqueous phase for high-speed shearing or ultrasonic emulsification to form an oil / water emulsion; finally, the organic solvent is evaporated by stirring, and PLA precipitates and deposits on the surface of AMC particles, forming a solidified microcapsule shell, which is then obtained after centrifugation, washing, and drying.

[0013] In the aforementioned slow-release marine antifouling coatings, the silane coupling agent is one or more of aminosilanes (such as KH-550, KH-792), epoxysilanes (such as KH-560), mercaptosilanes (such as KH-590), or vinylsilanes (such as A-171, A-151).

[0014] This invention utilizes amino acids (AMC) as a slow-release agent and auxiliary antifouling agent in ship hull antifouling coatings, offering unique advantages. Simultaneously, it enhances the coating's anti-corrosion performance. In the slightly alkaline environment of seawater, the protonation degree of AMC's amino groups decreases, increasing its solubility and specifically inhibiting localized corrosion. The coumarin structure of AMC possesses free radical scavenging capabilities, which can slow down the oxidation reaction on metal surfaces and extend the coating's lifespan. The amino (-NH2) and carbonyl (C=O) groups in the AMC molecule can act as coordinating groups, forming a dense chelate film with the ship hull's metal surface, blocking seawater and Cl-. - When in contact with corrosive media such as oxygen and oxygen (O2), the corrosion inhibition efficiency can reach 80%~90%, and it can synergistically enhance the overall protective effect with antifouling components. The coumarin structure of AMC undergoes a photolysis reaction under ultraviolet light irradiation, releasing active amino fragments, thereby regulating the release rate of the antifouling agent. On cloudy days / nighttime: the release rate decreases, reducing ineffective release; under strong light (summer / equatorial seas): release is accelerated to address the high risk of biofouling. Achieving on-demand release through photoresponsiveness, it can extend the antifouling cycle by 20%~30% compared to traditional constant-release coatings. In addition, AMC can disrupt the quorum sensing system of bacteria, preventing biofilm formation, and has an inhibition rate of ≥80% against sulfate-reducing bacteria (SRB) and algae. Its derivatives can interfere with the metamorphosis attachment process of barnacles, oysters, and other larvae, reducing the risk of hard biofouling. Compared to traditional slow-release agents and antifouling agents, AMC has extremely low toxicity to marine organisms, meeting IMO environmental requirements; furthermore, the coumarin derivatives are gradually decomposed by microorganisms in the natural environment, avoiding long-term cumulative pollution and possessing environmentally friendly characteristics. AMC also serves as a marker because it emits blue fluorescence when excited by ultraviolet light. Therefore, when the coating is damaged or the metal begins to corrode, the fluorescence intensity will decrease or shift, enabling early corrosion warning.

[0015] Secondly, the present invention provides a method for preparing the above-mentioned antifouling coating for marine hulls, comprising the following steps: AMC, DCOIT@SiO2 and quaternized chitosan were added to acetone and ultrasonically dispersed under ice bath conditions to obtain antifouling agent mother liquor; carbon nanotubes, fluorosilane-modified SiO2 and nano-Cu2O hollow spheres were added to anhydrous ethanol and ultrasonically dispersed to obtain reinforcing filler dispersion. While stirring, add the antifouling agent stock solution and reinforcing filler dispersion to the mixed epoxy resin and silane coupling agent; stir at low speed and add PLA@AMC microcapsules, and mix evenly.

[0016] In the above preparation method, the AMC used can be a commercially available product or can be prepared by the following method: 1,3-dihydroxy-5-chlorobenzene, ethyl acetoacetate, and N,N-dimethylformamide are placed in a reaction flask, and concentrated sulfuric acid is added dropwise at 40°C for 30 minutes under controlled temperature. The mixture is then slowly heated to 110±2°C and kept at this temperature for 6-8 hours. The reaction solution is then cooled to 10°C and refluxed for condensation. The mixture is filtered, and the filter cake is washed with distilled water to obtain a light yellow solid. The crude product is dissolved in an alkaline solution and filtered. An acid solution is added to the filtrate, and the precipitate is filtered. The precipitate is washed with ice water and then recrystallized from methanol to obtain the final product.

[0017] Preferably, in the above preparation method, the nano-Cu2O hollow spheres are prepared by the following method: S1. A soft template solution is prepared by adding polyvinylpyrrolidone (PVP) and sodium dodecyl sulfate (SDS) to water. The pH of the soft template solution is adjusted to alkaline after mixing with an aqueous solution of copper salt. The copper salt is selected from one or more of copper sulfate, copper chloride, copper sulfide, copper fluoride, copper nitrate, copper acetate, copper oxalate, basic copper carbonate, and basic copper sulfide. S2. Under stirring conditions, add the aqueous solution of hydrazine hydrate to the mixed solution obtained in step S1, and react at 40-60℃ to obtain a colloidal solution containing nano-Cu2O hollow spheres; S3. Centrifuge the colloidal solution, collect the precipitate, wash and dry it to obtain the final product.

[0018] More preferably, in step S1, the concentration of copper ions in the mixed solution is 10 mmol / L, the concentration of polyvinylpyrrolidone is 10 g / L, the concentration of sodium dodecyl sulfate is 45 mmol / L, and the pH is adjusted to 11 using sodium hydroxide, sodium carbonate, calcium hydroxide, or potassium carbonate; in step S2, 0.3-0.5 mL of 50 wt% hydrazine hydrate aqueous solution is added to each liter of the mixed solution; in step S3, the centrifugation conditions are 10,000 rpm for 10-15 min, and the washing is performed by alternating between deionized water and anhydrous ethanol multiple times.

[0019] Preferably, in the above preparation method, the amount of acetone used is 5-10 times the total weight of AMC, DCOIT@SiO2 and quaternized chitosan, and the amount of anhydrous ethanol used is 8-15 times the total weight of carbon nanotubes, fluorosilane-modified SiO2 and nano-Cu2O hollow spheres.

[0020] Preferably, in the above preparation method, an appropriate amount of PVP is added as a dispersing aid when preparing the reinforced filler dispersion.

[0021] Preferably, in the above preparation method, the epoxy resin is preheated to reduce its viscosity before being stirred and mixed with the silane coupling agent.

[0022] Thirdly, the present invention provides an antifouling coating film prepared from the marine hull antifouling coating of the present invention.

[0023] In some embodiments of the present invention, an antifouling coating was prepared using polyetheramine as a curing agent.

[0024] Fourthly, the present invention provides an antifouling substrate, which includes a substrate and an antifouling coating provided by the present invention, wherein the antifouling coating is attached to the substrate.

[0025] Compared with the prior art, the beneficial effects of the present invention are as follows: Compared to traditional antifouling coatings for ship hulls, the marine antifouling coating provided by this invention has significant advantages in antifouling efficiency, environmental friendliness, long-lasting effect, and multifunctional integration. Specifically, this invention selects epoxy resin with strong adhesion, corrosion resistance, high mechanical strength, and compatibility with functional fillers; nano-Cu2O hollow spheres with slow-release properties, high-efficiency antifouling, low environmental risk, and enhanced coating performance; and AMC with metal protection, environmental friendliness, intelligent response, and synergistic antifouling properties. Furthermore, the formulation design has been optimized, significantly improving the effective duration and antifouling performance of the antifouling coating, while achieving environmental friendliness and slow-release of the antifouling agent. At least in the following aspects: ① The synergistic effect of epoxy resin and nano-Cu2O hollow spheres can both inhibit the attachment of marine organisms and reduce the risk of localized corrosion; ② The polar molecular structure of epoxy resin facilitates the dispersion of nano-Cu2O hollow spheres and AMC, avoiding agglomeration and ensuring uniform release of functional components; ③ The nano-size of nano-Cu2O hollow spheres makes them easier to disperse uniformly in the epoxy resin matrix, reducing stress concentration and preventing coating cracking; ④ AMC is particularly suitable for use with the epoxy resin / nano-Cu2O hollow sphere system to construct an integrated "antifouling-slow release-self-monitoring" ship hull protective coating; ⑤ When nano-Cu2O in the coating releases Cu... + At this time, it may accelerate the electrochemical corrosion of the ship's hull metal, while AMC, by adsorbing onto the metal surface, blocks Cu²⁺ corrosion. + / Fe galvanic circuit, reducing local battery effect; ⑥ The amino group (-NH2) of AMC reacts with the epoxy group of epoxy resin, improving the compatibility of AMC in coatings, avoiding precipitation, and the decomposition temperature is >200℃, which is suitable for the curing process of epoxy resin. Detailed Implementation

[0026] The technical solution of the present invention will be described in detail below with reference to the embodiments.

[0027] Unless otherwise defined, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art; the terminology used herein is for the purpose of describing particular implementations only and is not intended to limit the invention.

[0028] To address the technical problems of existing antifouling coatings, such as unsatisfactory antifouling effect, short effective duration, uncontrollable release of antifouling agents, and pollution of the marine environment, this invention provides a novel marine antifouling coating for ship hulls. By optimizing the coating formulation, the antifouling performance and slow-release performance of the coating are improved, making it better able to cope with the complex marine environment.

[0029] The marine antifouling coating provided in this embodiment of the invention comprises the following raw materials: 50-60 parts epoxy resin, 5-10 parts nano-Cu2O hollow spheres, 1-3 parts AMC, 3-5 parts quaternized chitosan, 2-4 parts DCOIT@SiO2, 3-8 parts fluorosilane-modified SiO2, 0.5-2 parts carbon nanotubes, 5-10 parts PLA@AMC microcapsules, 1-3 parts silane coupling agent, by weight.

[0030] This invention also provides a method for preparing the above-mentioned antifouling coating for marine hulls, comprising the following steps: AMC, DCOIT@SiO2 and quaternized chitosan were added to acetone and ultrasonically dispersed under ice bath conditions to obtain antifouling agent mother liquor; carbon nanotubes, fluorosilane-modified SiO2 and nano-Cu2O hollow spheres were added to anhydrous ethanol and ultrasonically dispersed to obtain reinforcing filler dispersion. While stirring, add the antifouling agent stock solution and reinforcing filler dispersion to the mixed epoxy resin and silane coupling agent; stir at low speed and add PLA@AMC microcapsules, and mix evenly.

[0031] Furthermore, the above preparation method also includes the following steps: mixing the uniformly mixed coating system with a polyetheramine curing agent, and then preparing the coating after degassing.

[0032] The following are some specific embodiments. It should be noted that the embodiments described below are exemplary and are only used to explain the present invention, and should not be construed as limiting the present invention. Where specific techniques or conditions are not specified in the embodiments, they shall be performed in accordance with the techniques or conditions described in the literature in this field or according to the product instructions. Reagents or instruments used, unless otherwise specified, are all conventional products that can be obtained commercially.

[0033] The nano-Cu2O hollow spheres used in the following examples were prepared through the following steps: ① Add PVP and SDS to deionized water, heat to 50°C, and then cool to room temperature to obtain a soft template solution; ② Dissolve copper sulfate in deionized water to prepare a copper salt aqueous solution; ③ Mix the soft template solution with the copper salt aqueous solution until homogeneous. The resulting mixed solution contains 10 mmol / L copper ions, 10 g / L polyvinylpyrrolidone, and 45 mmol / L sodium dodecyl sulfate. ④ Adjust the pH of the mixed solution to 11 with sodium hydroxide to create a suitable alkaline environment; ⑤ Under stirring conditions, 50 wt% hydrazine hydrate aqueous solution was added to the above mixed solution (volume ratio of 0.4:1000). After uniform mixing, the solution was placed in a constant temperature water bath at 50℃ and allowed to stand for 60 minutes to form a colloidal solution containing nano-Cu2O hollow spheres. ⑥ Centrifuge the colloidal solution at 10,000 rpm for 15 minutes, collect the precipitate, and then wash the precipitate several times with deionized water and anhydrous ethanol alternately. Dry the washed precipitate in a low-temperature oven for 24 hours to obtain nano-Cu2O hollow spheres.

[0034] Example 1 A slow-release marine antifouling coating comprises the following raw materials: 60 parts of bisphenol A type epoxy resin, 5 parts of nano-Cu2O hollow spheres, 3 parts of AMC, 5 parts of quaternized chitosan, 4 parts of DCOIT@SiO2, 8 parts of fluorosilane-modified SiO2, 2 parts of carbon nanotubes, 10 parts of PLA@AMC microcapsules, and 3 parts of KH-550; by weight.

[0035] Its preparation method includes the following steps: (1) Add AMC, DCOIT@SiO2 and quaternized chitosan to 8 times the amount of acetone, and use an ultrasonic cell disruptor to sonicate for 30 minutes under ice bath conditions (to avoid local overheating and component degradation) to obtain the antifouling agent mother liquor; (2) Add the reinforcing filler carbon nanotubes, fluorosilane modified SiO2 and nano Cu2O hollow spheres to 10 times the amount of anhydrous ethanol and sonicate (350W power, 1 hour) until no visible agglomeration is observed; add 0.1wt% of PVP as a dispersing agent to obtain the product as a reinforcing filler dispersion.

[0036] (3) Preheat the epoxy resin at 60°C for 20 minutes to reduce its viscosity, then mix it with the silane coupling agent and mechanically stir for 30 minutes; then add the antifouling agent mother liquor and the reinforcing filler dispersion through a constant pressure dropping funnel, while increasing the stirring speed to 800 rpm and continuing for 1 hour.

[0037] (4) Add PLA@AMC microcapsules at room temperature with low stirring speed of 200 rpm for 15 minutes to avoid breakage and mix evenly.

[0038] Example 2 A slow-release marine antifouling coating comprises the following raw materials: 55 parts of bisphenol A type epoxy resin, 10 parts of nano-Cu2O hollow spheres, 2 parts of AMC, 4 parts of quaternized chitosan, 3 parts of DCOIT@SiO2, 6 parts of fluorosilane-modified SiO2, 1 part of carbon nanotubes, 5 parts of PLA@AMC microcapsules, and 2 parts of KH-550; by weight.

[0039] Its preparation method is the same as that in Example 1.

[0040] Example 3 A substrate with an antifouling coating is prepared by the following method: Using polyetheramine as a curing agent, it is rapidly stirred with the slow-release marine antifouling coating (epoxy:amine = 3:1 equivalent ratio) prepared in this invention for 5 minutes until homogeneous, and then vacuum degassed before being coated onto the substrate.

[0041] Comparative Example 1 An antifouling coating, the raw materials of which include: 60 parts of bisphenol A type epoxy resin, 5 parts of nano Cu2O hollow spheres, 3 parts of benzotriazole, 5 parts of quaternized chitosan, 4 parts of DCOIT@SiO2, 8 parts of fluorosilane modified SiO2, 2 parts of graphene, 10 parts of PLA@AMC microcapsules, and 3 parts of KH-550; by weight.

[0042] The preparation method is the same as in Example 1, except for the change of raw materials.

[0043] Comparative Example 2 An antifouling coating, the raw materials of which include: 60 parts polyurethane resin, 5 parts nano-Cu2O hollow spheres, 3 parts AMC, 5 parts quaternized chitosan, 4 parts DCOIT@SiO2, 8 parts fluorosilane-modified SiO2, 2 parts carbon nanotubes, 10 parts PLA@AMC microcapsules, and 3 parts KH-590; by weight.

[0044] The preparation method is the same as in Example 1, except for the change of raw materials.

[0045] Comparative Example 3 An antifouling coating, the raw materials of which include: 60 parts of bisphenol A type epoxy resin, 5 parts of micron-sized Cu2O solid particles (2-3μm), 3 parts of AMC, 5 parts of quaternized chitosan, 4 parts of DCOIT@SiO2, 8 parts of fluorosilane-modified SiO2, 2 parts of carbon nanotubes, 10 parts of PLA@AMC microcapsules, and 3 parts of KH-550; by weight.

[0046] The preparation method is the same as in Example 1, except for the change of raw materials.

[0047] Comparative Example 4 An antifouling coating, the raw materials of which include: 60 parts of bisphenol A type epoxy resin, 5 parts of nano Cu2O hollow spheres, 3 parts of pH-responsive chitosan microspheres, 5 parts of quaternized chitosan, 4 parts of DCOIT@SiO2, 8 parts of fluorosilane-modified SiO2, 2 parts of carbon nanotubes, 10 parts of PLA@AMC microcapsules, and 3 parts of KH-550; by weight.

[0048] The pH-responsive chitosan microspheres used were prepared by the following method: 1.5 g of chitosan was dissolved in 100 mL of 2% acetic acid solution and stirred until clear; under vigorous stirring, a mixture of 50 mL of liquid paraffin and 1.5 mL of Span-80 was added dropwise to emulsify and form a W / O type emulsion; 2 mL of 25% glutaraldehyde aqueous solution was slowly added as a crosslinking agent and reacted at 50 °C for 2 h; after the reaction was completed, the microspheres were collected by centrifugation, washed successively with petroleum ether, anhydrous ethanol and deionized water, and freeze-dried to obtain pH-responsive chitosan microspheres with a particle size of 50-100 μm.

[0049] The preparation method of the antifouling coating is the same as that in Example 1, except for the change of raw materials.

[0050] The antifouling coatings from Examples 1-2 and Comparative Examples 1-4 were prepared into coating films and subjected to the following performance tests: 1) Antifouling rate: The actual sea-hanging test was carried out with reference to "GB / T 5370-2007 Antifouling paint sample shallow sea immersion test method". After immersion for 6 months, the antifouling rate was calculated according to "GB / T 31817-2015 Antifouling paint antifouling performance dynamic test method".

[0051] 2) Cu + Slow-release period: In accordance with the provisions of ISO 15181-1:2019 Paints and varnishes — Determination of release rate of biocides from antifouling paints, the concentration of copper ions in artificial seawater is periodically determined by atomic absorption spectrometry (AAS) or inductively coupled plasma optical emission spectrometry (ICP-OES), and the time point when the concentration drops below the effective threshold is recorded as the slow-release endpoint.

[0052] 3) Adhesion: The pull-off adhesion test was conducted in accordance with ASTM D4541-17 Standard Test Method for Pull-Off Strength of Coatings Using Portable Adhesion Testers.

[0053] 4) Fluorescence monitoring: The fluorescence on the coating surface was observed using a digital microscope equipped with an ultraviolet light source (365nm), and the fluorescence uniformity and fluorescence changes at damaged areas were recorded.

[0054] 5) Ecotoxicity (LC) 50 ): Large-scale acute toxicity tests of Daphnia sp. were conducted in accordance with GB / T 21807-2008 Biodegradability Test in Seawater by Shake Flask Method and OECD 202:2004 Daphnia sp. Acute Immobilisation Test.

[0055] 6) Abrasion resistance: The test shall be conducted in accordance with GB / T 1768-2006 Determination of abrasion resistance of paints and varnishes by rotating rubber grinding wheel method. The result shall be expressed as mass loss (mg) after a certain number of revolutions.

[0056] 7) Impact resistance: The test shall be conducted in accordance with GB / T 20624.2-2006 Paints and Varnishes Rapid Deformation (Impact Resistance) Test Part 2: Drop Hammer Test, Small Area Punch. The result shall be expressed as the maximum height (cm) at which the heavy hammer does not cause damage to the coating.

[0057] 8) Pencil hardness: The test shall be conducted in accordance with GB / T 6739-2006 Pencil method for determining the hardness of paint and varnish.

[0058] 9) Tensile strength: The coating is made into a standard dumbbell-shaped specimen and tested on a universal testing machine in accordance with GB / T 1040.3-2006 Determination of tensile properties of plastics Part 3: Test conditions for films and sheets.

[0059] The test results are shown in the table below:

[0060] The test results show that the marine antifouling coating prepared in the embodiments of the present invention has excellent antifouling performance, slow-release performance, adhesion performance, and environmental safety performance. Especially in the seawater immersion test, the marine antifouling coating of the embodiments exhibits excellent antifouling performance and intelligent controlled release, while the antifouling coatings in the comparative examples show a significant performance decline. For example, the antifouling coating prepared with polyurethane resin in Comparative Example 2 has poor adhesion and antifouling / corrosion resistance, and there is a problem of incomplete integration with other components. Comparative Example 3, using micron-sized solid Cu2O particles, caused an increase in coating toxicity due to explosive release; the seawater exceeded the standard value in the early stages, and the antifouling effect was not achieved in the later stages. Comparative Example 4, using pH-responsive chitosan microspheres, could not monitor the coating status and had poor controlled release effect, with unsatisfactory initial release. By comparing the performance data of Examples 1-2 with Comparative Example 1, it can be seen that Comparative Example 1, without AMC, has better antifouling rate, Cu... + The release cycle and other key indicators are significantly lower than those of the embodiments of the present invention, and the fluorescence monitoring function is completely lost. This fully demonstrates that AMC is the core necessary component for realizing intelligent light-responsive release and coating condition self-monitoring functions. The photosensitive groups in its molecule can regulate the release of antifouling agents on demand, the bonding between amino groups and epoxy resins enhances compatibility, and the characteristic fluorescence signal provides real-time early warning for coating integrity. These synergistic effects together constitute the technical innovation of the present invention that distinguishes it from traditional antifouling coatings.

[0061] In summary, the slow-release marine antifouling coating provided by this invention has excellent antifouling performance, slow-release performance, adhesion performance and environmental safety performance, and can meet the needs of complex working conditions, especially suitable for use in harsh conditions such as seawater environment.

[0062] It should be noted that the present invention is not limited to the above-described embodiments. The above embodiments are merely examples, and any embodiments that have the same structure and perform the same effects as the technical concept within the scope of the present invention are included within the scope of the present invention. Furthermore, various modifications that can be conceived by those skilled in the art to the embodiments, and other ways of constructing by combining some of the constituent elements of the embodiments, without departing from the spirit of the present invention, are also included within the scope of the present invention.

Claims

1. A slow-release marine antifouling coating, characterized in that, It contains the following ingredients: 50-60 parts epoxy resin, 5-10 parts nano-cuprous oxide hollow spheres, 1-3 parts 7-amino-4-methylcoumarin, 3-5 parts quaternized chitosan, 2-4 parts DCOIT-supported mesoporous SiO2, 3-8 parts fluorosilane-modified SiO2, 0.5-2 parts carbon nanotubes, 5-10 parts PLA@AMC microcapsules, 1-3 parts silane coupling agent, by weight.

2. The slow-release marine antifouling coating according to claim 1, characterized in that, The nano-cuprous oxide hollow spheres are hollow sphere structures with porous shells, with a size of 50-300 nm, a shell thickness of 10-50 nm, and a pore size distribution of 5-25 nm on the shell.

3. A method for preparing the slow-release marine antifouling coating as described in claim 1 or 2, characterized in that, include: 7-Amino-4-methylcoumarin, DCOIT-supported mesoporous SiO2 and quaternized chitosan were added to acetone and ultrasonically dispersed under ice bath conditions to obtain antifouling agent mother liquor; carbon nanotubes, fluorosilane-modified SiO2 and nano-cuprous hollow spheres were added to anhydrous ethanol and ultrasonically dispersed to obtain reinforcing filler dispersion. While stirring, add the antifouling agent stock solution and the reinforcing filler dispersion to the mixture of epoxy resin and silane coupling agent; stir at low speed and add PLA@AMC microcapsules, and mix evenly.

4. The preparation method according to claim 3, characterized in that, The preparation method of the nano-cuprous oxide hollow spheres includes the following steps: S1. Polyvinylpyrrolidone and sodium dodecyl sulfate are added to water to prepare a soft template solution. The pH of the soft template solution is adjusted to alkaline after being mixed with copper salt aqueous solution. S2. Under stirring conditions, add the aqueous solution of hydrazine hydrate to the mixed solution obtained in step S1, and react at 40-60℃ to obtain a colloidal solution containing nano-cuprous oxide hollow spheres; S3. Centrifuge the colloidal solution, collect the precipitate, wash and dry it to obtain the final product.

5. The preparation method according to claim 4, characterized in that, The copper salt is one or more of copper sulfate, copper chloride, copper sulfide, copper fluoride, copper nitrate, copper acetate, copper oxalate, basic copper carbonate, and basic copper sulfide.

6. The preparation method according to claim 4, characterized in that, The mixed solution contains 10 mmol / L copper ions, 10 g / L polyvinylpyrrolidone, and 45 mmol / L sodium dodecyl sulfate; 0.3–0.5 mL of 50% hydrazine hydrate aqueous solution is added to each liter of the mixed solution.

7. The preparation method according to claim 6, characterized in that, The pH is 11.

8. An antifouling coating, characterized in that, It is formed from the slow-release marine antifouling coating as described in claim 1.

9. The antifouling coating according to claim 8, characterized in that, Antifouling coatings were prepared using polyetheramine as a curing agent.

10. A stain-resistant substrate, characterized in that, It includes a substrate and the antifouling coating as described in claim 8, wherein the antifouling coating is attached to the substrate.

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