A composite antifouling paint for freshwater zebra mussels and a method for preparing the same

Abstract

The application discloses a kind of composite antifouling paint for fresh water shell and preparation method thereof, the paint system takes bisphenol A type epoxy resin and polyamide curing agent as film-forming base material, core adds cashew phenol-based epoxy compatibilizing diluent, 1,8-eucalyptol / hydroxypropyl-β-cyclodextrin inclusion complex, lithium type 5Å molecular sieve and alpha-zirconium hydrogen phosphate nanosheet;The application eliminates the phase interface micro-pore through the bidirectional molecular bridging and hydrophobic synergy of cashew phenol-based diluent, greatly improves the long-term electrochemical impedance of coating;Innovatively use lithium type molecular sieve to release high-activity Li + , competitively inhibit the metal coordination crosslinking of fresh water shell foot silk protein, significantly interfere with the curing process of foot silk patch;At the same time, alpha-zirconium hydrogen phosphate is used to accurately buffer micro-zone pH and occur intercalation phase change self-healing, completely avoid coating penetration blistering;The antifouling mechanism of the application is unique, which realizes super-long effective environmental protection antifouling and physical corrosion protection.

Description

Technical Field

[0001] This invention relates to the field of coating technology, specifically to a composite antifouling coating for freshwater shellfish and its preparation method. Background Technology

[0002] The freshwater mussel, scientifically known as *Myriophyllum sp.*, also called the golden mussel, belongs to the family Myriophyllum, order Myriophyllum, class Bivalvia. Native to southern China and Southeast Asia, it has now widely invaded temperate and subtropical freshwater ecosystems worldwide due to human water transport and irrigation activities. This species exhibits strong environmental adaptability and reproductive capacity, capable of proliferating and establishing itself in large numbers in freshwater environments with temperatures ranging from 14 to 30°C and flow rates from 0.05 to 2.0 m / s. Its larvae (from trochophore to vegetal larvae) can be dispersed over long distances by water currents and firmly attach to various substrates using adhesive proteins secreted byssal threads.

[0003] Existing technologies for controlling freshwater shellfish mainly fall into three categories: physical removal, chemical methods, and antifouling coatings. Physical removal methods, including high-pressure water jet washing, mechanical scraping, and manual underwater cleaning, can achieve immediate removal, but their effectiveness against shellfish communities attached to complex internal structures, pipe bends, and grid crevices is limited. Furthermore, this method is a passive response measure, unable to prevent continuous reattachment, resulting in high maintenance frequency, labor intensity, and persistently high long-term costs. Chemical methods mainly involve adding biocides such as chlorine, sodium hypochlorite, potassium permanganate, quaternary ammonium salts, and glutaraldehyde to the water body. These can kill large numbers of larvae in a short period, but continuous application faces a series of serious challenges, including excessive pesticide residues, aquatic ecotoxicity, and compliance with drinking water safety regulations, severely limiting their applicability in drinking water source projects. In addition, chemical agents often fail to achieve the targeted control concentrations within various enclosed cavities in water conservancy projects, leading to unstable overall control effects.

[0004] Antifouling coatings, due to their advantages such as convenient application, long-term coexistence with substrates, and minimal maintenance, are considered the most promising proactive preventative solution for engineering applications and have received widespread research attention in recent years. However, existing antifouling coating technologies still face many unresolved technical challenges in the practical application of freshwater shellfish control, and their overall performance cannot yet meet the long-term service requirements of water conservancy projects.

[0005] In terms of coating durability and corrosion resistance, hydraulic engineering components are subjected to harsh conditions such as long-term immersion, alternating wet and dry conditions, or flowing scouring, which places extremely high demands on the adhesion, water resistance, and mechanical strength of the coating. Some existing antifouling coating systems have insufficient compatibility between the film-forming base material and the antifouling functional components, making them prone to multiphase separation during film formation. This results in discontinuous microporous channels within the coating, allowing water molecules and corrosive ions to penetrate rapidly along these channels. This causes premature degradation of the coating's electrochemical shielding performance, leading to macroscopic failure phenomena such as blistering, cracking, and peeling under long-term immersion conditions. The actual corrosion protection service life is far shorter than the design expectation.

[0006] Regarding the long-term release of antifouling active components, existing antifouling coatings typically rely on the physical dissolution mechanism of the antifouling agent within the coating. However, the inherent "burst release-depletion" effect of this mechanism causes a large release of antifouling activity in the early stages of coating service, leading to rapid depletion of the antifouling agent reserves and loss of antifouling activity in the later stages of coating operation. This fails to meet the 3-5 year long-term antifouling cycle required by engineering projects. Furthermore, some antifouling active substances (such as natural terpenoid volatile oils) are highly volatile and have low water solubility, making it difficult to maintain effective concentrations within the activity threshold range required to inhibit shellfish attachment in open water environments, significantly reducing antifouling efficiency.

[0007] In targeted interventions against the adhesion of byssal threads in freshwater shellfish, current technologies fall short in utilizing the molecular mechanisms of this adhesion. The byssal proteins of freshwater shellfish are rich in 3,4-dihydroxyphenylalanine (DOPA) functional groups, which are involved in Fe... 3+ Ca 2+ Oxidative curing occurs under the coordination crosslinking of polyvalent metal ions, endowing byssal silk patches with super strong wet adhesion. Most existing antifouling coatings rely on the physical barrier effect of low surface energy hydrophobic coatings, which can only increase the thermodynamic energy barrier of initial adhesion and have a very limited effect on reducing the adhesion of already cured and crosslinked byssal silk patches. Reports on antifouling technologies that can actively intervene in the coordination crosslinking process of byssal silk proteins at the chemical mechanism level and block the curing of byssal silk from the source are still rare, and the formulation and application of related functional components lack systematic research.

[0008] In conclusion, developing a novel composite antifouling coating that combines long-lasting anti-corrosion and shielding properties, controlled and slow-release properties of antifouling active substances, and synergistic intervention capabilities through multiple mechanisms for the adhesion of freshwater shellfish byssal threads is of great practical significance for improving the safe operation of large-scale water conservancy projects in my country and reducing the cost of biofouling prevention and control. Technological innovation and breakthroughs are urgently needed in related fields. Summary of the Invention

[0009] To address the shortcomings of existing technologies, the present invention aims to provide a composite antifouling coating for freshwater shellfish and its preparation method. The present invention achieves excellent antifouling and physical-mechanical properties through the synergistic effect of specific components, particularly by introducing an inclusion complex, a cashew phenolic epoxidizing compatibilizer and diluent, a lithium-type 5Å molecular sieve, and α-zirconium hydrogen phosphate nanosheets.

[0010] To achieve the above objectives, the present invention adopts the following technical solution: This invention provides a composite antifouling coating for freshwater shellfish. The coating composition, by weight, comprises: 40-55 parts of bisphenol A type epoxy resin; 20-35 parts of polyamide curing agent; 15-23 parts of pigments and fillers; 0.5-1.0 parts of additives; 15-20 parts of mixed solvent; 6-10 parts of inclusion complex; 10-18 parts of cashew phenolic epoxidative compatibilizer and diluent; 5-12 parts of lithium-type 5Å molecular sieve; and 1.5-2.5 parts of α-zirconium hydrogen phosphate nanosheets.

[0011] Furthermore, as preferred parameters for the coating film-forming base and functional modifier of the present invention, the bisphenol A type epoxy resin is a commercially available conventional coating-grade resin, and its epoxy equivalent is preferably 450~500 g / eq; the amine value of the polyamide curing agent is preferably 180~220 mgKOH / g. The molecular structure of the cashew phenol-based epoxidative compatibilizer and diluent simultaneously contains epoxy groups and C 15 Unsaturated alkyl side chains and phenolic hydroxyl groups have the functions of compatibilizing, diluting and participating in curing and cross-linking.

[0012] Furthermore, the pigments and fillers are composed of rutile titanium dioxide, talc, and precipitated barium sulfate, with a mass ratio of rutile titanium dioxide, talc, and precipitated barium sulfate of 10~15:5~10:5~8; the additives are composed of polyether-modified silicone leveling agents and non-silicone polymer defoamers, with a mass ratio of polyether-modified silicone leveling agents to non-silicone polymer defoamers of 0.3~0.6:0.2~0.4; the mixed solvent is a mixture of xylene and n-butanol, with a volume ratio of xylene to n-butanol of 6:4~8:2. All of the above raw materials can be obtained through commercial channels.

[0013] Further, the inclusion complex is prepared by the following steps: under light-protected conditions, 1,8-cineole with a purity ≥95% and hydroxypropyl-β-cyclodextrin with an inner diameter of 6.0~6.5 Å are mixed in deionized water, stirred to induce the inclusion reaction, and then dried to obtain the inclusion complex.

[0014] The specific process parameters are as follows: the molar ratio of 1,8-cineole to hydroxypropyl-β-cyclodextrin is 1:1 to 1:1.2; the amount of deionized water used is 5 to 10 times the mass of hydroxypropyl-β-cyclodextrin; the stirring temperature is 30 to 50°C, and the time is 12 to 24 hours; the drying is freeze-drying at a temperature of -40°C to 50°C for 24 to 48 hours; and the inclusion constant K of the obtained inclusion complex is 500 to 1500 M. -1 .

[0015] Furthermore, the α-zirconium hydrogen phosphate nanosheets are prepared by the following method steps: (1) Hydrothermal synthesis stage: ZrOCl2·8H2O was dissolved in a phosphoric acid solution with a concentration of 3~6 mol / L, wherein the mass-volume ratio of ZrOCl2·8H2O to the phosphoric acid solution was 80~120 g / L; the reaction was refluxed at 85~100℃ for 24~48 hours, and after the reaction was completed, the mixture was filtered and washed with deionized water until neutral, and then dried under vacuum at 60℃ to obtain α-zirconium hydrogen phosphate precursor powder; (2) Intercalation and exfoliation stage: The obtained α-zirconium hydrogen phosphate is dispersed in an aqueous solution of n-butylamine (the mass fraction of n-butylamine is 10%~20%), and the solid-liquid mass-volume ratio of α-zirconium hydrogen phosphate to the aqueous solution of n-butylamine is 50~100 g / L; the reaction is stirred for 12~24 hours to allow it to be fully exfoliated, then centrifuged and collected, excess n-butylamine is washed away, and dried at 60~80℃ to obtain α-zirconium hydrogen phosphate nanosheets with layered structure unfolded.

[0016] Furthermore, the lithium-type 5Å molecular sieve is prepared by the following method steps: After grinding the 5Å sodium-type molecular sieve powder, water flow classification was performed, controlling the upward flow velocity of the water flow classification to be 1.5~2.5 cm / s, and collecting powder with a D50 median particle size of 2.5~3.5 μm. The obtained powder was dispersed in a lithium chloride solution with a concentration of 0.8~1.2 mol / L, wherein the solid-liquid mass-to-volume ratio of the 5Å sodium-type molecular sieve powder to the lithium chloride solution was 80~120 g / L. The mixture was heated and stirred at 75~85℃ for 5~7 hours to achieve sufficient lithium-ion exchange. After the reaction was completed, the mixture was filtered and washed with deionized water until no chloride ions were detected in the filtrate by silver nitrate detection. Finally, the mixture was dried at 120℃ to obtain a lithium-type 5Å molecular sieve with a lithium-ion exchange degree ≥85%.

[0017] The present invention also provides a method for preparing the above-mentioned composite antifouling coating for freshwater shellfish, comprising the following steps: At room temperature (approximately 25°C), using a high-shear dispersion device, the cashew phenol-based epoxidized compatibilizer and lithium-type 5Å molecular sieve are first mixed and dispersed at a speed of 1200-1600 r / min for 5-10 minutes; then α-zirconium hydrogen phosphate nanosheets are added and dispersed at 1200-1600 r / min for another 5-10 minutes; then the pre-prepared inclusion complex, pigments, fillers, and additives are added, and the mixture is continued to be mixed and dispersed at a speed of 1200-1600 r / min, so that the total dispersion time of component A reaches 20-40 minutes, resulting in a uniform component A (main agent); before construction, component A is mixed with polyamide curing agent according to the specified ratio, and after stirring evenly, it can be applied to obtain the composite antifouling coating.

[0018] Compared with the prior art, the present invention has the following beneficial effects: This invention provides a composite antifouling coating. Through a scientifically formulated ratio of film-forming base material, inorganic filler, and functional modifier, a dense physical anti-corrosion foundation and stable surface and interface characteristics are established. In the system, bisphenol A epoxy resin and polyamide curing agent undergo an amine-epoxy ring-opening addition reaction, constructing a high-density three-dimensional cross-linked polymer network. Combined with the physical filling effects of rutile titanium dioxide, talc, and precipitated barium sulfate, the coating's permeability to water molecules and corrosive ions is significantly reduced. Simultaneously, the cashew phenol-based epoxidizing compatibilizer and diluent not only adjusts the system viscosity but also, through its C... 15 After long-chain nonpolar alkyl groups are covalently incorporated into the resin network, the surface free energy of the coating is effectively reduced, and the hydrophobicity of the coating film is improved. This increases the thermodynamic resistance to the initial attachment of aquatic organisms such as freshwater shellfish at the physical level, ensuring the basic service life and mechanical stability of the coating in water conservancy engineering environments.

[0019] In underwater hanging and accelerated immersion experiments on freshwater shellfish, the applicant unexpectedly discovered that, according to conventional polymer physical blending theory, due to the continuous penetration of water molecules into the coating, this type of coating rich in inorganic salts (molecular sieves) and water-soluble inclusions would inevitably experience blistering due to the osmotic pressure gradient, accompanied by alkaline hydrolytic degradation of the polymer network. However, the experimental results showed that the coating of this invention not only did not exhibit any osmotic pressure blistering or microporous formation, but its long-term mechanical resistance also showed abnormal stability. Even more unusually, in the freshwater shellfish adhesion experiment, the byssal patch curing process was significantly disturbed, resulting in a substantial decrease in the degree of keratinization and a reduction in patch adhesion force by about an order of magnitude. This led to a non-linear and extremely large leap in the actual effective antifouling effect of the coating, achieving unexpected technical results.

[0020] The unusual mechanical stability may be attributed to the bidirectional molecular bridging effect of the cashew phenolic epoxide compatibilizer / diluent in the system: its epoxy groups form ring-opening covalent bonds with the silanol groups on the surface of the lithium-type 5Å molecular sieve, while the phenolic hydroxyl groups form a multi-hydrogen bond network with hydroxypropyl-β-cyclodextrin. This interaction uniformly and densely anchors the inorganic molecular sieve and organic supramolecular inclusion complex within the epoxy crosslinking network, eliminating microscopic pores at the phase interface from a thermodynamic perspective, significantly improving the initial overall electrochemical impedance of the coating, and hindering the random diffusion of water molecules.

[0021] Regarding the phenomenon of hindered solidification of the byssal fibers of freshwater clams, the applicant speculates that when a very small amount of water molecules penetrate into the coating surface, the Li in the lithium-type 5Å molecular sieve... + With Ca in environmental water bodies 2+ Mg 2+ Competitive ion exchange occurs, with a large amount of active Li + Released into the coating / water interface micro-region, simultaneously consuming the Ca originally dissolved in the interfacial water film. 2+ Mg 2+ Isovalent cations. This process synergistically intervenes in the byssal adhesion mechanism of freshwater shellfish on two levels: firstly, the dissolved Li + Diffusion to the coating / water interface, competitive coordination occurs with the 3,4-dihydroxyphenylalanine (DOPA) group in the byssal protein of freshwater shellfish, Li + Although its coordination ability is weaker than Ca 2+ Fe 3+ While polyvalent metal ions are present, their high local concentration can effectively occupy the coordination active sites of the DOPA group, hindering the entry of polyvalent metal ions through steric hindrance, thus preventing the normal DOPA-mediated coordination cross-linking reaction of byssal precursor proteins; secondly, the interfacial microregion Ca 2+ Mg 2+ The significant reduction in concentration directly deprives the byssal proteins of the necessary metal ion substrate supply to complete oxidative cross-linking and curing. The synergistic effect of the above dual intervention prevents the secreted byssal patches from completing the transformation from precursor proteins to a cured keratinized state. Macroscopically, this manifests as transparent gel-like byssal patches that cannot undergo dark keratinization and disintegrate upon slight touch, thus completely depriving freshwater shellfish of their effective adhesion ability from the perspective of macromolecular chemical cross-linking mechanism.

[0022] The coating generates Li + If alkaline degradation and osmotic foaming do not occur during the exchange, it may stem from spontaneous microenvironment pH regulation and phase transition healing mechanisms within the system. Theoretically, Li + / H +Ion exchange continuously generates lithium hydroxide, leading to localized strong alkalinization. The α-zirconium hydrogen phosphate nanosheets in the nitrogen system play a dual regulatory role in this process: firstly, when the local pH rises to around 9.5, the hydrogen phosphate ions on the surface of the α-zirconium hydrogen phosphate undergo a step-proton dissociation, neutralizing excess OH-. - This precisely buffers the microenvironment pH within a safe range (8.5–9.5) suitable for inclusion complex dissociation, preventing the hydrolysis of the epoxy polymer network. On the other hand, layered α-zirconium hydrogen phosphate selectively captures free Li through ion intercalation. + The process generates insoluble solid crystals, which not only eliminates the osmotic pressure gradient of lithium hydroxide in situ, but also causes a lattice volume expansion effect that spontaneously fills the microcracks in the polymer network caused by early water penetration through physical compression. This micro-lattice expansion triggered by ion exchange achieves "self-healing" of physical defects in the coating, thereby completely suppressing coating failure and creating its unexpectedly long antifouling period. Detailed Implementation

[0023] To make the objectives, technical solutions, and advantages of this invention clearer, the invention will be further described in detail below with reference to embodiments. Of course, the specific embodiments described herein are only for explaining the invention and are not intended to limit the invention.

[0024] Unless otherwise specified, all chemical reagents and materials in this invention are purchased from the market or synthesized from raw materials purchased from the market.

[0025] 1. Core Modifying Materials and Resin System: 1,8-Cineole: Purity ≥95%, naturally extracted or synthetic grade, commercially available common fragrances or chemical reagents.

[0026] Hydroxypropyl-β-cyclodextrin: pharmaceutical or food grade, with its cavity diameter strictly controlled within the range of 6.0~6.5 Å, and the degree of substitution is conventional.

[0027] Bisphenol A type epoxy resin: industrial coating grade, epoxy equivalent in the range of 450~500g / eq (such as commercially available E-20 type or similar solid / semi-solid epoxy resin).

[0028] Polyamide curing agent: industrial coating grade, amine value in the range of 180~220mgKOH / g (such as commercially available 650 type polyamide resin or similar grades).

[0029] Cashew Nut Phenolic Epoxidation Compatibilizer and Diluent: Industrial grade, purified from natural cashew nut shell extract (containing C) 15 Commercially available reactive diluents (such as commercially available NC-513 or brands with equivalent structures) are partially epoxidized from unsaturated alkyl side chains and phenolic hydroxyl groups.

[0030] 2. Basic Inorganic Materials and Chemical Reagents: 5Å Sodium Molecular Sieves Raw Powder: Industrial-grade sodium aluminum silicate crystalline micronized powder with a pore size of approximately 5Å, a conventional commercially available raw powder that has not undergone other metal ion exchange treatment.

[0031] Pigments and fillers: rutile titanium dioxide, talc, and precipitated barium sulfate, all of which are conventional industrial coating grade with a D50 particle size distribution (e.g., 800~1250 mesh).

[0032] Coating additives: polyether modified silicone leveling agents (such as BYK-346 or similar brands), non-silicone polymer defoamers (such as BYK-052 or similar brands).

[0033] Mixed solvents: xylene and n-butanol, both industrial grade or analytical grade, with a moisture content ≤0.1%.

[0034] Inorganic salts and acid-base reagents: zirconium oxychloride (ZrOCl2·8H2O), phosphoric acid (H3PO4), n-butylamine, lithium chloride (LiCl), and silver nitrate (AgNO3) were all analytical grade (AR) reagents. All laboratory water was prepared deionized water.

[0035] 3. Comparative example of specific alternative materials: Silica micro powder: used in Comparative Example 1, commercially available coating-grade inert filler with an average particle size of approximately 5 μm.

[0036] Sodium-based montmorillonite nanosheets: used in Comparative Example 3, commercially available highly exfoliated two-dimensional inorganic layered material with a median D50 particle size of approximately 1-2 μm and a specific surface area of ​​approximately 700-800 m² / g.

[0037] Butyl glycidyl ether (BGE): Used in Comparative Example 4, with a purity ≥98%, commercially available conventional monofunctional aliphatic epoxy reactive diluent (free of phenolic hydroxyl groups and long-chain alkyl groups).

[0038] A method for preparing a composite antifouling coating for freshwater shellfish includes the following steps: (1) Under light-protected conditions, 1,8-cineole with a purity ≥95% and hydroxypropyl-β-cyclodextrin with an inner diameter of 6.0~6.5 Å are mixed in deionized water at a molar ratio of 1:1~1.2, with the amount of deionized water being 5~10 times the mass of hydroxypropyl-β-cyclodextrin. The reaction is carried out at a constant temperature of 30~50℃ with stirring for 12~24 hours. After the reaction is completed, the mixture is dried (preferably freeze-dried at -40℃~-50℃ for 24~48 hours; or spray-dried) to obtain an inclusion constant K of 500~1500 M. -1 The inclusion complex solid powder between them.

[0039] (2) Dissolve ZrOCl2·8H2O in a phosphoric acid solution with a concentration of 3~6 mol / L, and control the mass-to-volume ratio of ZrOCl2·8H2O to phosphoric acid solution to be 80~120 g / L. Reflux the reaction at 85~100℃ for 24~48 hours. After the reaction is complete, filter and wash with deionized water until neutral. Dry under vacuum at 60℃ to obtain the α-zirconium hydrogen phosphate precursor. (3) The α-zirconium hydrogen phosphate precursor was dispersed in an aqueous solution of n-butylamine with a mass fraction of 10%~20% and the solid-liquid mass-volume ratio was controlled at 50~100 g / L. The mixture was stirred at room temperature for 12~24 hours to perform intercalation and exfoliation. The mixture was then centrifuged and washed to remove free n-butylamine. The mixture was dried at 60~80℃ to obtain two-dimensional layered α-zirconium hydrogen phosphate nanosheets.

[0040] (4) After grinding the 5Å sodium-type molecular sieve raw powder, water flow classification was performed, controlling the upward flow velocity of the water flow classification to be 1.5~2.5 cm / s, and collecting the powder with a D50 median particle size of 2.5~3.5 μm. The collected powder was dispersed in a lithium chloride solution with a concentration of 0.8~1.2 mol / L, and the solid-liquid mass-volume ratio of the powder to the lithium chloride solution was controlled to be 80~120 g / L. Ion exchange was carried out by heating and stirring at 75~85℃ for 5~7 hours. The solution was filtered and washed with deionized water until no chloride ions were found in the filtrate (no white precipitate was detected by AgNO3 solution). Finally, it was dried at a constant temperature of 120℃ to obtain a lithium-type 5Å molecular sieve with a lithium ion exchange degree ≥85%.

[0041] (5) At room temperature, perform high-shear dispersion in the following order (the dispersion speed in each step is controlled at 1200~1600 r / min): First, mix 10~18 parts of cashew phenolic epoxidative compatibilizer and 5~12 parts of lithium-type 5Å molecular sieve, and disperse for 5~10 minutes; add 1.5~2.5 parts of α-zirconium hydrogen phosphate nanosheets, and continue mixing and dispersing for 5~10 minutes; add 6~10 parts of inclusion complex, 40~55 parts of bisphenol A type epoxy resin, and 15~23 parts of pigments and fillers ( The mixture consists of rutile titanium dioxide, talc, and precipitated barium sulfate in a mass ratio of 10-15:5-10:5-8, 0.5-1.0 parts of additives (polyether-modified silicone leveling agent and non-silicone polymer defoamer in a mass ratio of 0.3-0.6:0.2-0.4), and 15-20 parts of mixed solvent (xylene and n-butanol in a volume ratio of 6:4-8:2). The mixture is then further mixed and dispersed to ensure that the total dispersion time of component A reaches 20-40 minutes, and a uniformly dispersed component A is obtained by discharging the product.

[0042] (6) Before application, take the A component prepared above, add 20-35 parts of polyamide curing agent and mix evenly to obtain the composite antifouling coating for freshwater shellfish. Apply it by brushing, rolling or spraying to the surface of the hydraulic engineering substrate and cure at room temperature to form a dense antifouling coating.

[0043] The present invention will be further described below through specific embodiments.

[0044] Example 1 A method for preparing a composite antifouling coating for freshwater shellfish includes the following steps: (1) Under light-protected conditions, 15.4 g (0.100 mol) of 1,8-cineole with a purity ≥95% was mixed with 152.5 g (0.110 mol) of hydroxypropyl-β-cyclodextrin (cavity inner diameter 6.2 Å, molar ratio 1:1.1) in 1144 g of deionized water (7.5 times the mass of hydroxypropyl-β-cyclodextrin), and stirred at 40 °C for 18 hours. After the reaction was completed, the mixture was freeze-dried at -45 °C for 36 hours to obtain a solid powder of inclusion complex. The inclusion constant K was determined to be approximately 1000 M. -1 .

[0045] (2) Dissolve 100.0g ZrOCl2·8H2O in 1000mL of 4.5mol / L phosphoric acid solution (solid-liquid mass-volume ratio 100g / L), reflux at 92℃ for 36 hours, filter and wash with deionized water until neutral, and vacuum dry at 60℃ to obtain α-zirconium hydrogen phosphate precursor.

[0046] (3) Disperse 75.0g of the α-zirconium hydrogen phosphate precursor obtained in step (2) in 1000mL of 15% n-butylamine aqueous solution (solid-liquid mass-volume ratio 75g / L), stir at room temperature for 18 hours to perform intercalation and exfoliation, centrifuge and wash repeatedly with deionized water to remove free n-butylamine, and dry at 70℃ to obtain two-dimensional layered α-zirconium hydrogen phosphate nanosheets.

[0047] (4) The 5Å sodium-type molecular sieve powder was ground and then subjected to water flow classification. The upward flow velocity was controlled at 2.0 cm / s, and the powder with a median D50 particle size of 3.0 μm was collected. 100.0 g of powder was dispersed in 1000 mL of lithium chloride solution with a concentration of 1.0 mol / L (solid-liquid mass-volume ratio 100 g / L), and heated and stirred at 80 °C for 6 hours for ion exchange. The solution was filtered and washed with deionized water until no white precipitate was detected by AgNO3 solution. The solution was then dried at 120 °C to obtain lithium-type 5Å molecular sieve with a lithium ion exchange degree ≥85%.

[0048] (5) At room temperature, high shear dispersion was carried out in the following order, with the dispersion speed controlled at 1400 r / min in each step: First, 14.0 g of cashew phenolic epoxidative compatibilizer and 8.5 g of lithium-type 5 Å molecular sieve obtained in step (4) were mixed and dispersed for 7 minutes; 2.0 g of α-zirconium hydrogen phosphate nanosheets obtained in step (3) were added and mixed and dispersed for another 7 minutes; 8.0 g of inclusion complex obtained in step (1) and 47.5 g of bisphenol A type epoxy resin were added. The following ingredients were added: epoxy equivalent (475 g / eq), 19.0 g pigments and fillers (12.5 g rutile titanium dioxide, 4.0 g talc, 2.5 g precipitated barium sulfate), 0.75 g additives (0.45 g polyether modified silicone leveling agent, 0.30 g non-silicone polymer defoamer), and 17.5 g mixed solvent (xylene and n-butanol volume ratio 7:3). The mixture was continued to be mixed and dispersed. The total dispersion time of component A was controlled at 30 minutes. The product was then discharged as a uniformly dispersed component A.

[0049] (6) Before application, take component A above, add 27.5g of polyamide curing agent (amine value 200mgKOH / g), mix and stir evenly to obtain the composite antifouling coating of Example 1. Apply it by brushing, rolling or spraying to the surface of the hydraulic engineering substrate, and cure at room temperature to form a dense antifouling coating.

[0050] Example 2 A method for preparing a composite antifouling coating for freshwater shellfish includes the following steps: (1) Under light-protected conditions, 15.4 g (0.100 mol) of 1,8-cineole with a purity ≥95% was mixed with 166.4 g (0.120 mol) of hydroxypropyl-β-cyclodextrin (cavity inner diameter 6.5 Å, molar ratio 1:1.2) in 1664 g of deionized water (10 times the mass of hydroxypropyl-β-cyclodextrin), and stirred at 50 °C for 12 hours. After the reaction was completed, the mixture was freeze-dried at -40 °C for 24 hours to obtain the inclusion complex solid powder.

[0051] (2) Dissolve 120.0g ZrOCl2·8H2O in 1000mL of 6.0mol / L phosphoric acid solution (solid-liquid mass-volume ratio 120g / L), reflux at 100℃ for 24 hours, filter and wash with deionized water until neutral, and dry under vacuum at 60℃ to obtain α-zirconium hydrogen phosphate precursor.

[0052] (3) Disperse 100.0g of the α-zirconium hydrogen phosphate precursor obtained in step (2) in 1000mL of 20% n-butylamine aqueous solution (solid-liquid mass-volume ratio 100g / L), stir at room temperature for 12 hours to perform intercalation and exfoliation, centrifuge and wash repeatedly with deionized water to remove free n-butylamine, and dry at 80℃ to obtain two-dimensional layered α-zirconium hydrogen phosphate nanosheets.

[0053] (4) The 5Å sodium-type molecular sieve powder was ground and then subjected to water flow classification. The upward flow velocity was controlled at 2.5 cm / s, and the powder with a median D50 particle size of 2.5 μm was collected. 120.0 g of powder was dispersed in 1000 mL of lithium chloride solution with a concentration of 1.2 mol / L (solid-liquid mass-volume ratio 120 g / L), and heated and stirred at 85 °C for 5 hours for ion exchange. The solution was filtered and washed with deionized water until no white precipitate was detected by AgNO3 solution. The solution was then dried at 120 °C to obtain a lithium-type 5Å molecular sieve with a lithium ion exchange degree ≥85%.

[0054] (5) At room temperature, high shear dispersion was carried out in the following order, with the dispersion speed controlled at 1600 r / min in each step: First, 18.0 g of cashew phenolic epoxidative compatibilizer and 12.0 g of lithium-type 5 Å molecular sieve obtained in step (4) were mixed and dispersed for 10 minutes; 2.5 g of α-zirconium hydrogen phosphate nanosheets obtained in step (3) were added and mixed and dispersed for another 10 minutes; 10.0 g of inclusion complex obtained in step (1) and 55.0 g of bisphenol A type epoxy were added. The resin (epoxy equivalent 500g / eq), 23.0g pigments and fillers (rutile titanium dioxide 15.0g, talc 5.0g, precipitated barium sulfate 3.0g), 1.0g additives (polyether modified silicone leveling agent 0.60g, non-silicone polymer defoamer 0.40g) and 20.0g mixed solvent (xylene and n-butanol volume ratio 8:2) were mixed and dispersed. The total dispersion time of component A was controlled at 40 minutes, and the uniformly dispersed component A was discharged.

[0055] (6) Before application, take component A above, add 35.0g of polyamide curing agent (amine value 220mgKOH / g), mix and stir evenly to obtain the composite antifouling coating of Example 2. Apply it by brushing, rolling or spraying to the surface of the hydraulic engineering substrate, and cure at room temperature to form a dense antifouling coating.

[0056] Example 3 A method for preparing a composite antifouling coating for freshwater shellfish includes the following steps: (1) Under light-protected conditions, 15.4 g (0.100 mol) of 1,8-cineole with a purity ≥95% was mixed with 138.6 g (0.100 mol) of hydroxypropyl-β-cyclodextrin (cavity inner diameter 6.0 Å, molar ratio 1:1.0) in 693 g of deionized water (5 times the mass of hydroxypropyl-β-cyclodextrin), and stirred at 30 °C for 24 hours. After the reaction was completed, the mixture was freeze-dried at -50 °C for 48 hours to obtain a solid powder of the inclusion complex.

[0057] (2) Dissolve 80.0g ZrOCl2·8H2O in 1000mL of 3.0mol / L phosphoric acid solution (solid-liquid mass-volume ratio 80g / L), reflux at 85℃ for 48 hours, filter and wash with deionized water until neutral, and vacuum dry at 60℃ to obtain α-zirconium hydrogen phosphate precursor.

[0058] (3) Disperse 50.0g of the α-zirconium hydrogen phosphate precursor obtained in step (2) in 1000mL of 10% n-butylamine aqueous solution (solid-liquid mass-volume ratio 50g / L), stir at room temperature for 24 hours to perform intercalation and exfoliation, centrifuge and wash repeatedly with deionized water to remove free n-butylamine, and dry at 60℃ to obtain two-dimensional layered α-zirconium hydrogen phosphate nanosheets.

[0059] (4) The 5Å sodium-type molecular sieve powder was ground and then subjected to water flow classification. The upward flow velocity was controlled at 1.5 cm / s, and the powder with a median D50 particle size of 3.5 μm was collected. 80.0 g of the powder was dispersed in 1000 mL of 0.8 mol / L lithium chloride solution (solid-liquid mass-volume ratio 80 g / L), and heated and stirred at 75 °C for 7 hours for ion exchange. The solution was filtered and washed with deionized water until no white precipitate was detected by AgNO3 solution. The solution was then dried at 120 °C to obtain a lithium-type 5Å molecular sieve with a lithium ion exchange degree ≥85%.

[0060] (5) At room temperature, high shear dispersion was carried out in the following order, with the dispersion speed controlled at 1200 r / min in each step: First, 10.0 g of cashew phenolic epoxidative compatibilizer and 5.0 g of lithium-type 5 Å molecular sieve obtained in step (4) were mixed and dispersed for 5 minutes; 1.5 g of α-zirconium hydrogen phosphate nanosheets obtained in step (3) were added and mixed and dispersed for another 5 minutes; 6.0 g of inclusion complex obtained in step (1) and 40.0 g of bisphenol A type epoxy resin were added. The following ingredients were added: epoxy equivalent 450 g / eq, 15.0 g pigments and fillers (rutile titanium dioxide 10.0 g, talc 3.0 g, precipitated barium sulfate 2.0 g), 0.5 g additives (polyether modified silicone leveling agent 0.30 g, non-silicone polymer defoamer 0.20 g), and 15.0 g mixed solvent (xylene and n-butanol volume ratio 6:4). The mixture was continued to be mixed and dispersed. The total dispersion time of component A was controlled to be 20 minutes. The product was then discharged to obtain a uniformly dispersed component A.

[0061] (6) Before application, take component A above, add 20.0g of polyamide curing agent (amine value 180mgKOH / g), mix and stir evenly to obtain the composite antifouling coating of Example 3. Apply it by brushing, rolling or spraying to the surface of the hydraulic engineering substrate, and cure at room temperature to form a dense antifouling coating.

[0062] Comparative Example 1 The only difference between this comparative example and Example 1 is that hydroxypropyl-β-cyclodextrin is omitted in step (1), the inclusion operation is not performed, and an equimolar amount of free 1,8-cineole is directly added to the system. At the same time, an equal mass of silica micro powder (average particle size of about 5 μm, inert filler) is used to make up the mass difference corresponding to the omission of cyclodextrin. The amount of all other components and the preparation process of each step are exactly the same as in Example 1.

[0063] A method for preparing a composite antifouling coating for freshwater shellfish includes the following steps: (1) Weigh 15.4g (0.100mol) of free 1,8-cineole with a purity ≥95%, without performing inclusion operation, and set aside directly. Weigh 152.5g of silica micro powder (average particle size of about 5μm) for use in step (5) to make up the total solid content of the formula.

[0064] (2) Dissolve 100.0g ZrOCl2·8H2O in 1000mL of 4.5mol / L phosphoric acid solution (solid-liquid mass-volume ratio 100g / L), reflux at 92℃ for 36 hours, filter and wash with deionized water until neutral, and vacuum dry at 60℃ to obtain α-zirconium hydrogen phosphate precursor.

[0065] (3) Disperse 75.0g of the α-zirconium hydrogen phosphate precursor obtained in step (2) in 1000mL of 15% n-butylamine aqueous solution (solid-liquid mass-volume ratio 75g / L), stir at room temperature for 18 hours to perform intercalation and exfoliation, centrifuge and wash repeatedly with deionized water to remove free n-butylamine, and dry at 70℃ to obtain two-dimensional layered α-zirconium hydrogen phosphate nanosheets.

[0066] (4) The 5Å sodium-type molecular sieve powder was ground and then subjected to water flow classification. The upward flow velocity was controlled at 2.0 cm / s, and the powder with a median D50 particle size of 3.0 μm was collected. 100.0 g of powder was dispersed in 1000 mL of lithium chloride solution with a concentration of 1.0 mol / L (solid-liquid mass-volume ratio 100 g / L), and heated and stirred at 80 °C for 6 hours for ion exchange. The solution was filtered and washed with deionized water until no white precipitate was detected by AgNO3 solution. The solution was then dried at 120 °C to obtain lithium-type 5Å molecular sieve with a lithium ion exchange degree ≥85%.

[0067] (5) At room temperature, high shear dispersion was carried out in the following order, with the dispersion speed controlled at 1400 r / min in each step: First, 14.0 g of cashew phenol-based epoxidative compatibilizer and 8.5 g of lithium-type 5 Å molecular sieve obtained in step (4) were mixed and dispersed for 7 minutes; 2.0 g of α-zirconium hydrogen phosphate nanosheets obtained in step (3) were added and mixed and dispersed for another 7 minutes; 15.4 g of free 1,8-cineole obtained in step (1) and 47.5 g of bisphenol A were added. Epoxy resin (epoxy equivalent 475 g / eq), 19.0 g pigments and fillers (12.5 g rutile titanium dioxide, 4.0 g talc, 2.5 g precipitated barium sulfate), 0.75 g additives (0.45 g polyether modified silicone leveling agent, 0.30 g non-silicone polymer defoamer), and 17.5 g mixed solvent (xylene and n-butanol volume ratio 7:3) were mixed and dispersed. The total dispersion time of component A was controlled at 30 minutes, and component A was discharged.

[0068] (6) Before application, take component A above, add 27.5g of polyamide curing agent (amine value 200mgKOH / g), mix and stir evenly to obtain the coating of Comparative Example 1. Apply it by brushing, rolling or spraying to the surface of the hydraulic engineering substrate, and cure at room temperature to form a coating.

[0069] Comparative Example 2 The only difference between this comparative example and Example 1 is that the water flow classification and lithium chloride ion exchange operations are omitted in step (4), and the lithium 5Å molecular sieve is directly replaced with an equal mass of 5Å sodium molecular sieve raw powder (without particle size classification and ion exchange treatment). The amount of all other components and the preparation process of each step are exactly the same as in Example 1.

[0070] A method for preparing a composite antifouling coating for freshwater shellfish includes the following steps: (1) Under light-protected conditions, 15.4 g (0.100 mol) of 1,8-cineole with a purity ≥95% was mixed with 152.5 g (0.110 mol) of hydroxypropyl-β-cyclodextrin (cavity inner diameter 6.2 Å, molar ratio 1:1.1) in 1144 g of deionized water (7.5 times the mass of hydroxypropyl-β-cyclodextrin) and stirred at 40 °C for 18 hours. After the reaction was completed, the mixture was freeze-dried at -45 °C for 36 hours to obtain the inclusion complex solid powder.

[0071] (2) Dissolve 100.0g ZrOCl2·8H2O in 1000mL of 4.5mol / L phosphoric acid solution (solid-liquid mass-volume ratio 100g / L), reflux at 92℃ for 36 hours, filter and wash with deionized water until neutral, and vacuum dry at 60℃ to obtain α-zirconium hydrogen phosphate precursor.

[0072] (3) Disperse 75.0g of the α-zirconium hydrogen phosphate precursor obtained in step (2) in 1000mL of 15% n-butylamine aqueous solution (solid-liquid mass-volume ratio 75g / L), stir at room temperature for 18 hours to perform intercalation and exfoliation, centrifuge and wash repeatedly with deionized water to remove free n-butylamine, and dry at 70℃ to obtain two-dimensional layered α-zirconium hydrogen phosphate nanosheets.

[0073] (4) Skip the water flow classification and lithium chloride ion exchange operations, directly grind the 5Å sodium molecular sieve raw powder (D50 median particle size is not controlled, about 15~30μm) and dry it at 120℃ for later use, weigh 8.5g for later use.

[0074] (5) At room temperature, high shear dispersion was carried out in the following order, with the dispersion speed controlled at 1400 r / min in each step: First, 14.0 g of cashew phenolic epoxidation compatibilizer and 8.5 g of the 5 Å sodium molecular sieve raw powder obtained in step (4) were mixed and dispersed for 7 minutes; 2.0 g of α-zirconium hydrogen phosphate nanosheets obtained in step (3) were added and mixed and dispersed for another 7 minutes; 8.0 g of the inclusion complex obtained in step (1) and 47.5 g of bisphenol A type ring were added. The following ingredients were added: epoxy resin (epoxy equivalent 475 g / eq), 19.0 g pigments and fillers (12.5 g rutile titanium dioxide, 4.0 g talc, 2.5 g precipitated barium sulfate), 0.75 g additives (0.45 g polyether modified silicone leveling agent, 0.30 g non-silicone polymer defoamer), and 17.5 g mixed solvent (xylene and n-butanol volume ratio 7:3). The mixture was further mixed and dispersed, with the total dispersion time of component A controlled at 30 minutes. Component A was then discharged.

[0075] (6) Before application, take component A above, add 27.5g of polyamide curing agent (amine value 200mgKOH / g), mix and stir evenly to obtain the coating of Comparative Example 2. Apply it by brushing, rolling or spraying to the surface of the hydraulic engineering substrate, and cure at room temperature to form a coating.

[0076] Comparative Example 3 The only difference between this comparative example and Example 1 is that the entire preparation process of α-zirconium hydrogen phosphate nanosheets is omitted in steps (2) and (3), and is directly replaced by an equal mass of sodium-based montmorillonite nanosheets (commercially available, median D50 particle size of about 1~2 μm, specific surface area of ​​about 700 m² / g). The amounts of all other components and the preparation processes of each step are exactly the same as in Example 1. A method for preparing a composite antifouling coating for freshwater shellfish includes the following steps: (1) Under light-protected conditions, 15.4 g (0.100 mol) of 1,8-cineole with a purity ≥95% was mixed with 152.5 g (0.110 mol) of hydroxypropyl-β-cyclodextrin (cavity inner diameter 6.2 Å, molar ratio 1:1.1) in 1144 g of deionized water (7.5 times the mass of hydroxypropyl-β-cyclodextrin) and stirred at 40 °C for 18 hours. After the reaction was completed, the mixture was freeze-dried at -45 °C for 36 hours to obtain the inclusion complex solid powder.

[0077] (2) Skip the hydrothermal synthesis of the α-zirconium hydrogen phosphate precursor and directly weigh 2.0 g of commercially available sodium-based montmorillonite nanosheets (D50 median particle size of about 1~2 μm) for use in step (5). There are no other operations in this step.

[0078] (3) The intercalation and stripping operation of the α-zirconium hydrogen phosphate precursor is omitted. There are no other operations in this step.

[0079] (4) The 5Å sodium-type molecular sieve powder was ground and then subjected to water flow classification. The upward flow velocity was controlled at 2.0 cm / s, and the powder with a median D50 particle size of 3.0 μm was collected. 100.0 g of powder was dispersed in 1000 mL of lithium chloride solution with a concentration of 1.0 mol / L (solid-liquid mass-volume ratio 100 g / L), and heated and stirred at 80 °C for 6 hours for ion exchange. The solution was filtered and washed with deionized water until no white precipitate was detected by AgNO3 solution. The solution was then dried at 120 °C to obtain lithium-type 5Å molecular sieve with a lithium ion exchange degree ≥85%.

[0080] (5) At room temperature, high shear dispersion was carried out in the following order, and the dispersion speed of each step was controlled at 1400 r / min: First, 14.0 g of cashew phenolic epoxidative compatibilizer and 8.5 g of lithium-type 5 Å molecular sieve obtained in step (4) were mixed and dispersed for 7 minutes; 2.0 g of sodium-based montmorillonite nanosheets prepared in step (2) were added and mixed and dispersed for another 7 minutes; 8.0 g of inclusion complex obtained in step (1), 47.5 g of bisphenol A type epoxy resin (epoxy equivalent 475 g / eq), 19.0 g of pigments and fillers (12.5 g of rutile titanium dioxide, 4.0 g of talc, 2.5 g of precipitated barium sulfate), 0.75 g of additives (0.45 g of polyether modified organosilicon leveling agent, 0.30 g of non-silicone polymer type defoamer) and 17.5 g of mixed solvent (xylene and n-butanol volume ratio 7:3) were added and mixed and dispersed. The total dispersion time of component A was controlled at 30 minutes, and component A was obtained by discharge.

[0081] (6) Before application, take component A above, add 27.5g of polyamide curing agent (amine value 200mgKOH / g), mix and stir evenly to obtain the coating of Comparative Example 3. Apply it by brushing, rolling or spraying to the surface of the hydraulic engineering substrate, and cure at room temperature to form a coating.

[0082] Comparative Example 4 The only difference between this comparative example and Example 1 is that in step (5), the cashew phenolic epoxidizing diluent is replaced with an equal mass of butyl glycidyl ether (BGE, monofunctional aliphatic glycidyl ether, purity ≥98%). The amounts of all other components and the preparation processes of each step are exactly the same as in Example 1.

[0083] A method for preparing a composite antifouling coating for freshwater shellfish includes the following steps: (1) Under light-protected conditions, 15.4 g (0.100 mol) of 1,8-cineole with a purity ≥95% was mixed with 152.5 g (0.110 mol) of hydroxypropyl-β-cyclodextrin (cavity inner diameter 6.2 Å, molar ratio 1:1.1) in 1144 g of deionized water (7.5 times the mass of hydroxypropyl-β-cyclodextrin) and stirred at 40 °C for 18 hours. After the reaction was completed, the mixture was freeze-dried at -45 °C for 36 hours to obtain the inclusion complex solid powder.

[0084] (2) Dissolve 100.0g ZrOCl2·8H2O in 1000mL of 4.5mol / L phosphoric acid solution (solid-liquid mass-volume ratio 100g / L), reflux at 92℃ for 36 hours, filter and wash with deionized water until neutral, and vacuum dry at 60℃ to obtain α-zirconium hydrogen phosphate precursor.

[0085] (3) Disperse 75.0g of the α-zirconium hydrogen phosphate precursor obtained in step (2) in 1000mL of 15% n-butylamine aqueous solution (solid-liquid mass-volume ratio 75g / L), stir at room temperature for 18 hours to perform intercalation and exfoliation, centrifuge and wash repeatedly with deionized water to remove free n-butylamine, and dry at 70℃ to obtain two-dimensional layered α-zirconium hydrogen phosphate nanosheets.

[0086] (4) The 5Å sodium-type molecular sieve powder was ground and then subjected to water flow classification. The upward flow velocity was controlled at 2.0 cm / s, and the powder with a median D50 particle size of 3.0 μm was collected. 100.0 g of powder was dispersed in 1000 mL of lithium chloride solution with a concentration of 1.0 mol / L (solid-liquid mass-volume ratio 100 g / L), and heated and stirred at 80 °C for 6 hours for ion exchange. The solution was filtered and washed with deionized water until no white precipitate was detected by AgNO3 solution. The solution was then dried at 120 °C to obtain lithium-type 5Å molecular sieve with a lithium ion exchange degree ≥85%.

[0087] (5) At room temperature, high shear dispersion was carried out in the following order, with the dispersion speed controlled at 1400 r / min in each step: First, 14.0 g of butyl glycidyl ether (BGE, monofunctional aliphatic glycidyl ether, C-free) was dispersed. 15The alkyl side chain (without phenolic hydroxyl groups) was mixed with 8.5g of the lithium-type 5Å molecular sieve obtained in step (4) and dispersed for 7 minutes; 2.0g of α-zirconium hydrogen phosphate nanosheets obtained in step (3) were added and mixed and dispersed for another 7 minutes; 8.0g of the inclusion complex obtained in step (1), 47.5g of bisphenol A type epoxy resin (epoxy equivalent 475g / eq), 19.0g of pigments and fillers (12.5g of rutile titanium dioxide, 4.0g of talc, 2.5g of precipitated barium sulfate), 0.75g of additives (0.45g of polyether modified organosilicon leveling agent, 0.30g of non-silicone polymer type defoamer) and 17.5g of mixed solvent (xylene and n-butanol volume ratio 7:3) were added and mixed and dispersed. The total dispersion time of component A was controlled to be 30 minutes, and component A was discharged.

[0088] (6) Before application, take component A above, add 27.5g of polyamide curing agent (amine value 200mgKOH / g), mix and stir evenly to obtain the coating of Comparative Example 4. Apply it by brushing, rolling or spraying to the surface of the hydraulic engineering substrate, and cure at room temperature to form a coating.

[0089] I. Experimental Testing Methods 1. Basic hydrophobicity and long-term electrochemical impedance spectroscopy (evaluation of corrosion resistance and interface stability) Water contact angle (WCA): The static water contact angle was measured using a contact angle measuring instrument after the coating had cured at room temperature for 7 days. Five locations were measured in parallel for each group, and the average value ± standard deviation was taken.

[0090] EIS electrochemical impedance spectroscopy: The coated sample (coating area 1 cm², the remaining surface sealed with paraffin) was immersed in 3.5 wt% NaCl solution. Using a saturated calomel electrode as the reference electrode and a platinum sheet as the counter electrode, the impedance modulus (|Z|) in the low-frequency region (0.01 Hz) was measured on day 1 and day 180 of immersion. 0.01 (Hz, unit: Ω·cm²), three parallel samples were used in each group, and the mean ± standard deviation was taken to evaluate the degree of microporosity inside the coating and the separation of interfacial phases.

[0091] 2. Core antifouling agent slow-release kinetics and microenvironment pH monitoring 1,8-Cineole cumulative release rate: The coated sample was placed in a closed circulating leaching tank (deionized water, constant temperature 25±1℃). Samples were taken from the circulating tank periodically and immediately stored at -20℃. The release amount was determined by gas chromatography. The initial 1,8-cineole loading in the coating (calculated from the theoretical mass of 1,8-cineole in the inclusion complex) was used as 100% baseline. The fractional release rate and cumulative release rate on day 30, day 90 and day 180 were calculated.

[0092] Microenvironment pH test: A surface micro-area pH electrode (Ag / AgCl reference, measurement range 2~14, resolution 0.1 pH unit) was used to measure the micro-area pH value at the coating / water interface immediately after the sample was immersed in the immersion solution for 180 days. Five different locations were measured for each sample, and the mean ± standard deviation was taken.

[0093] 3. Evaluation of the curing state of the byss wire and accelerated bubbling during immersion in water. Juvenile freshwater shellfish (shell length 5-8 mm) from the same batch were introduced and placed in a circulating water tank containing a sample (water temperature 20±1℃, pH=7.5-8.0, Ca...). 2+ After inducing natural adhesion at a concentration of 50±5 mg / L for 72 hours, the sample was removed and evaluated from two dimensions: (1) Morphological observation of byssal patches: The morphology of byssal patches was observed under a stereomicroscope (×40x). Patches that were dark brown and had a dense and intact keratinized layer were considered "normal curing". Patches that were transparent or light yellow, had a discontinuous keratinized layer, and had irregular shrinkage at the edges were considered "curing hindered". At least 15 byssal patches were observed in parallel in each group, and the percentage of "curing hindered" was recorded (%).

[0094] (2) Byssal patch adhesion force determination: A micro-force sensor (range 0~500μN, resolution 0.1μN) was used to perform normal peel test on a single byssal patch, and the maximum desorption force (μN / patch) was used to characterize the byssal adhesion strength. No less than 10 patches were randomly measured in each group, and the mean ± standard deviation was taken.

[0095] Foaming rating: According to ASTM D714 standard, samples soaked for 180 days were visually rated for foaming (10 for no foaming, 8 for a small amount of foaming, 6 for moderate foaming, and 4 for severe foaming). The rating was blinded by 3 independent operators to obtain a consistent conclusion.

[0096] 4. Long-term antifouling test of hanging panels in real waters Each set of samples (150mm×100mm×3mm, single-sided coating, with the remaining sides and edges sealed with epoxy putty) was suspended in a water conservancy hub area with a high incidence of freshwater clams (water depth 2m, water temperature 10~28℃ (seasonal), water pH 7.2~7.8, conductivity 200~350μS / cm, local freshwater clams population density approximately 500~800 individuals / m²). One set of samples was retrieved at 6, 12, 18, and 24 months after installation. Image analysis software was used to binarize the front images of the coating, and the projected area coverage (%) of the freshwater clams (including byssal patches and shells) was calculated. Three parallel samples were used in each set, and the mean ± standard deviation was taken. This paper reports the data from the 24th month.

[0097] II. Experimental Data Results Table Table 1. Experimental test results of the examples and comparative examples. The coating impedance in Examples 1-3 remained consistently at 10. 9 The Ω·cm² level and initial water contact angle >94° indicate that the C in the cashew phenol-based diluent are high. 15 Unsaturated alkyl chains are effectively embedded in the curing network, reducing the surface free energy of the coating. Simultaneously, the phenolic hydroxyl groups form a hydrogen bond network with hydroxypropyl-β-cyclodextrin, uniformly anchoring the inclusion complex within the epoxy matrix and eliminating interfacial micropores. Comparative Example 4 uses a coating without phenolic hydroxyl groups and C... 15 After long-chain BGE replaces cashew phenol diluent, C 15 The hydrophobic effect is lost, and the initial contact angle drops to 71.5°; the phenolic hydroxyl bridging effect disappears, resulting in insufficient compatibility between the inclusion compound and the molecular sieve and the epoxy network interface, leading to the appearance of microporous channels within the coating, and the initial impedance drops to 3.8 × 10⁻⁶. 8 Ω·cm², which further decreased to 9.2×10 after 180 days due to continuous water infiltration. 6 At Ω·cm², moderate foaming of level 6 was observed. This data set confirms that the "two-way bridging" mechanism of cashew phenol-based diluents cannot be replaced by conventional short-chain aliphatic diluents.

[0098] In Comparative Example 1, 1,8-cineole was directly dispersed in the coating system in free form, with a cumulative release rate of nearly 95% after 180 days. The antifouling agent experienced a severe burst release in the early stages (within 30 days), and the antifouling reserve approached zero in the later stages, resulting in a vegetable coverage rate as high as 75% after 24 months of application. In Examples 1-3, after inclusion with cyclodextrin, the release rate after 180 days was only 38.6%-47.3%, indicating that the release of 1,8-cineole from its self-inclusion complex was diffusion-controlled, extending the effective antifouling period to over 360 days, thus ensuring long-term antifouling efficacy. This comparison directly confirms the necessity and irreplaceable role of host-guest inclusion with hydroxypropyl-β-cyclodextrin in the sustained release of antifouling agents.

[0099] Comparative Example 2 replaced the lithium-type 5Å molecular sieve with 5Å sodium-type molecular sieve powder, and no Li was present in the system. + In the observation experiment on byssal curing, the morphological characteristics of the byssal patches secreted by *Ligustrum lucidum* were normal dark brown keratinized curing, with a curing resistance rate of less than 10% and an adhesion force as high as 138.5 ± 19.4 μN / patch. In contrast, the curing resistance rate of byssal patches in Examples 1-3 was ≥80%, and the adhesion force was only 7.8-12.3 μN / patch, a reduction of approximately 11-18 times compared to Comparative Example 2. This fully demonstrates that *Ligustrum lucidum*... + It significantly interferes with the metal coordination crosslinking process of byssal proteins; on the other hand, it synergistically maintains the micro-region pH in a weakly alkaline range with α-ZrP, thus providing a suitable environment for Li +The sustained and stable release provides a favorable electrochemical gradient environment.

[0100] Comparative Example 3 replaced α-zirconium hydrogen phosphate nanosheets with sodium-based montmorillonite nanosheets. Although the coating still contained lithium-type molecular sieves, it could continuously release Li. + However, montmorillonite does not have a hydrogen phosphate buffering function, Li + Displaced Ca 2+ / Mg 2+ The accumulation of alkaline substances in the environment caused the pH of the coating / water interface micro-region to surge to 10.8, triggering strong alkaline hydrolysis of the coating's polymer matrix and a sharp increase in the osmotic pressure gradient. After 180 days, severe blistering of grade 4 occurred, and the impedance plummeted to 4.5 × 10⁻⁶. 6 Ω·cm², the coating blistered and peeled off over a large area, and the antifouling effect completely failed (85% coverage after 24 months). In contrast, the P-OH groups of the α-zirconium hydrogen phosphate nanosheets in Examples 1-3 formed HPO4 under alkaline conditions. 2- / H2PO4 - The buffer pair maintains the pH of the micro-region within a safe window, while the Zr-OP lattice undergoes reversible expansion during water molecule intercalation, filling microcrack channels and achieving a chemical self-healing effect. The impedance remains at 10⁻⁶ after 180 days. 9 The scale and foaming rating were all 10, which fully verified the necessity of the dual functions of precise pH control and lattice phase transition self-healing of α-zirconium hydrogen phosphate nanosheets.

[0101] The above description is only a preferred embodiment of the present invention, but the scope of protection of the present invention is not limited thereto. Any equivalent substitutions or modifications made by those skilled in the art within the scope of the technology disclosed in the present invention, based on the technical solution and inventive concept of the present invention, should be covered within the scope of protection of the present invention.

Claims

1. A composite antifouling coating for freshwater shellfish, characterized in that, The composition of the coating, by weight parts, comprises: 40-55 parts of bisphenol A type epoxy resin; 20-35 parts of polyamide curing agent; 15-23 parts of pigments and fillers; 0.5-1.0 parts of additives; 15-20 parts of mixed solvent; 6-10 parts of inclusion complex; 10-18 parts of cashew phenolic epoxidative compatibilizer and diluent; 5-12 parts of lithium-type 5Å molecular sieve; and 1.5-2.5 parts of α-zirconium hydrogen phosphate nanosheets.

2. The composite antifouling coating according to claim 1, characterized in that, The inclusion complex was prepared by the following steps: 1,8-cineole and hydroxypropyl-β-cyclodextrin were mixed in water under light-protected conditions, stirred, and dried to obtain the inclusion complex.

3. The composite antifouling coating according to claim 2, characterized in that, The purity of 1,8-cineole is ≥95%, and the cavity inner diameter of hydroxypropyl-β-cyclodextrin is 6.0~6.5 Å; the molar ratio of 1,8-cineole to hydroxypropyl-β-cyclodextrin is 1:1~1:1.2, and the amount of water used is 5~10 times the mass of hydroxypropyl-β-cyclodextrin; the stirring temperature is 30~50℃, and the time is 12~24 hours; the drying is done by freeze drying at -40℃~-50℃ for 24~48 hours; the inclusion constant K of the resulting inclusion complex is 500~1500M. -1 .

4. The composite antifouling coating according to claim 1, characterized in that, The α-zirconium hydrogen phosphate nanosheets were prepared by the following steps: (1) Dissolve ZrOCl2·8H2O in phosphoric acid solution, reflux the reaction, filter, wash, and dry to obtain α-zirconium hydrogen phosphate; (2) Disperse α-zirconium hydrogen phosphate in an aqueous solution of n-butylamine, stir, centrifuge, wash and dry to obtain α-zirconium hydrogen phosphate nanosheets.

5. The composite antifouling coating according to claim 4, characterized in that, In step (1), the concentration of phosphoric acid solution is 3~6 mol / L, and the mass-to-volume ratio of ZrOCl2·8H2O to phosphoric acid solution is 80~120 g / L; the reflux reaction temperature is 85~100℃, and the time is 24~48 hours; the drying is vacuum drying at 60℃; in step (2), the mass fraction of n-butylamine in the n-butylamine aqueous solution is 10%~20%, and the solid-liquid mass-to-volume ratio of α-zirconium hydrogen phosphate to n-butylamine aqueous solution is 50~100 g / L; the stirring time is 12~24 hours; and the drying temperature is 60~80℃.

6. The composite antifouling coating according to claim 1, characterized in that, The lithium-type 5Å molecular sieve is prepared by the following steps: grinding the raw powder of 5Å sodium-type molecular sieve, performing water flow classification, and collecting the powder; dispersing the obtained powder in a lithium chloride solution, heating and stirring to perform ion exchange, filtering, washing, and drying to obtain the lithium-type 5Å molecular sieve.

7. A method for preparing the composite antifouling coating as described in any one of claims 1 to 6, characterized in that, The process includes the following steps: at room temperature, cashew phenol-based epoxidized compatibilizer and lithium-type 5Å molecular sieve are first mixed and dispersed, then α-zirconium hydrogen phosphate nanosheets are added and mixed and dispersed, then inclusion complex, pigments, fillers and additives are added and mixed and dispersed to obtain component A, and finally component A is mixed with polyamide curing agent to obtain the composite antifouling coating.

8. The preparation method according to claim 7, characterized in that, The dispersion time of the cashew phenol-based epoxidized compatibilizer and the lithium-type 5Å molecular sieve is 5-10 minutes; the dispersion time after adding α-zirconium hydrogen phosphate nanosheets is 5-10 minutes; the rotation speed of each mixing and dispersion step is 1200-1600 r / min; the total dispersion time of component A is 20-40 minutes.

9. The composite antifouling coating according to claim 1, characterized in that, The bisphenol A type epoxy resin has an epoxy equivalent of 450~500 g / eq; the polyamide curing agent has an amine value of 180~220 mgKOH / g; the cashew phenol-based epoxidative compatibilizer diluent contains epoxy groups and C in its molecular structure. 15 Unsaturated alkyl side chains and phenolic hydroxyl groups.

10. The composite antifouling coating according to claim 1, characterized in that, The pigments and fillers are composed of rutile titanium dioxide, talc, and precipitated barium sulfate, with a mass ratio of 10~15:5~10:5~8. The additives are composed of polyether-modified silicone leveling agent and non-silicone polymer defoamer, with a mass ratio of 0.3~0.6:0.2~0.

4. The mixed solvent is a mixture of xylene and n-butanol, with a volume ratio of 6:4~8:2.

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