A dual-degradable resin, a preparation method thereof, an antifouling agent system, a marine antifouling composition and application thereof

Abstract

The application belongs to the field of new materials, and discloses a double-degradation resin, which is prepared by anionic hybrid copolymerization of six-membered ring lactide, acrylate and capsaicin acrylate; the application also discloses a preparation method of the double-degradation resin, and discloses an antifouling agent system, which comprises an antifouling agent and micro-nano particles, the micro-nano particles have a hollow cavity and a mesoporous surface, and the antifouling agent is loaded in the hollow cavity of the micro-nano particles; and discloses a marine antifouling composition formed based on the double-degradation resin and the antifouling agent system and application thereof. The application introduces a degradable polyester segment into the resin main chain, so that the resin can be self-degraded under the action of seawater, enzymes or microorganisms; the design enables the paint film to realize active polishing by main chain rupture under the condition of basically not relying on water flow scouring, and effectively prevents the attachment of fouling organisms; the capsaicin unit suspended on the side chain can also be hydrolyzed and exert real-time antifouling activity; the double-degradation resin meets the special requirements of static marine engineering facilities such as offshore wind power foundations on polishing performance.

Description

Technical Field

[0001] This invention belongs to the field of new materials, and particularly relates to a dual-degradable resin and its preparation method, an antifouling agent system, a marine antifouling composition and its application. Background Technology

[0002] With the continuous emergence of numerous offshore wind power / solar and other new energy facilities, their foundations, due to long-term immersion in seawater, inevitably suffer from the attachment, reproduction, and fouling of various marine organisms, which may lead to a chain of problems such as platform imbalance and reduced load-bearing capacity. To meet the requirements of ultra-long design life (mostly 25 years), applying antifouling coatings to the surface of the submerged area is one of the most cost-effective and ideal methods.

[0003] The key components of antifouling coatings are film-forming resins and antifouling agents. Antifouling agents should possess characteristics such as low toxicity and broad spectrum to efficiently kill as many adhering organisms as possible without harming the marine environment. Furthermore, the choice of carrier method is crucial to ensure the long-term continuous action of the antifouling agent. Simple physical blending is prone to "explosive release," making microencapsulation or porous adsorption the best choices for achieving controlled release. Microcapsule preparation is complex, requiring the capsules to be hydrophobic and oleophobic, and to maintain stability in organic solvents and seawater for a certain period. Patents such as CN102293198A, CN101137288A, KR101253065B1, JP2008513475A, and WO2006032019A1 all use 4,5-dichloro-2-n-octyl-4-isothiazolin-3-one (DCOIT) as the core material, and obtain water-in-oil core-shell capsules through multiple processes. Using the natural pores of diatomaceous earth, activated carbon, sepiolite, halloysite, and nanotubes as drug storage containers is relatively simple, but these materials mostly have narrow pore sizes (2-50 nm) and limited pore volume, making high-throughput drug loading difficult. Patents US6676954B2 and CN1229022C disclose a controlled-release composition in which activated carbon has a DCOIT loading of approximately 30%. Wang Xiaowei (Fine Chemicals, 2007, 24(10):944-947; 2007, 24(3):213-220) encapsulated DCOIT with copper microspheres and nano-titanium tubes, respectively, but the drug loading was low, with a maximum of only 15.2% and 12%. Zhang Xin (Surface Technology, 2024, 53(8):107-118) encapsulated carboxylated 1,2-benzisothiazolin-3-one (BIT-COOH) in amino / ZIF-7 (NH2-ZIF-7) nanocages by impregnation. Although the large size of the nanocages was beneficial, the drug loading was only 65.83%.

[0004] Regarding film-forming resins, in terms of self-polishing technology, unlike marine antifouling paints (which accelerate paint layer renewal and promote the shearing of marine organisms through the relative shear between ship navigation and water flow), offshore wind power / solar / ranch / beacon / floating valve, oil and gas drilling platforms, and other facilities are all in a fixed state. Once barnacles, mussels, etc., adhere to them, they are difficult to remove with the help of water flow, and their fouling is more rapid and severe. This, to a certain extent, requires film-forming resins to have lower hardness and modulus, and a faster degradation (polishing) rate. According to research, Jotun's Seamate and Seaquantum series from Norway, Hempel's Oceanic, Olympic, and Globic series from Denmark, and PPG's Sailadvance and ABC series of self-polishing paints all use the "acrylic resin + Cu2O" route and are only for ship hull coating. Currently, there are no mature products available domestically or internationally that are fully adapted to static marine engineering applications. Summary of the Invention

[0005] The technical problem to be solved by the present invention is to overcome the deficiencies and defects mentioned in the background art above, and to provide a dual-degradable resin and its preparation method, an antifouling agent system, a marine antifouling composition and its application.

[0006] To solve the above-mentioned technical problems, the technical solution proposed by this invention is as follows:

[0007] A dual-degradable resin, the structure of which is shown in Formula I: , Formula I Where R1 is -H or -CH3, R2 is any one of -CH3, -CH2CH3, -CH2CH2CH3, and -CH(CH3)2, and x, y, and z are independent positive integers.

[0008] Preferably, the aforementioned dual-degradable resin is prepared by anionic hybrid copolymerization of a six-membered cyclolactone, an acrylate, and a capsaicin acrylate.

[0009] Preferably, the six-membered cyclic lactone in the above-mentioned dual-degradable resin is at least one of glycolide, L-lactide, D-lactide, and racemic lactide; The acrylate is at least one of methyl acrylate, ethyl acrylate, propyl acrylate, isopropyl acrylate, methyl methacrylate, ethyl methacrylate, propyl methacrylate, and isopropyl methacrylate. The capsaicin acrylate is prepared by esterification of capsaicin with acryloyl halide or methacryloyl halide.

[0010] As part of the overall inventive concept, this invention also provides a method for preparing a dual-degradable resin, comprising the following steps: (1) Capsaicin, organic solvent A, acid-binding agent and acryloyl halide are mixed and reacted in a protective atmosphere, washed and dried to obtain capsaicin acrylate; wherein the acryloyl halide is acryloyl chloride or methacryloyl chloride; (2) The six-membered cyclolactone, acrylate and capsaicin acrylate obtained in step (1) are dissolved in organic solvent B, a catalyst and an initiator are added, and anionic hybrid copolymerization occurs in a protective atmosphere. After the reaction is completed, the resin is purified and dried to obtain the dual-degradable resin.

[0011] In the above preparation method, preferably, in step (1), the molar ratio of capsaicin, acid-binding agent and acryloyl halide is (1.0~1.2):(1.0~1.2):1.0; the reaction temperature is 0~4℃ and the reaction time is 3~7h.

[0012] In the above preparation method, preferably, in step (2), the molar ratio of the six-membered cyclolactone, acrylate and capsaicin acrylate is (0.9-1.3):1.0:(1.0-1.3), and the molar ratio of the initiator, catalyst and acrylate is (0.01-0.03):(0.01-0.03):1.0; the temperature of the anionic hybrid copolymerization reaction is 20-30℃, and the reaction time is 6-10h.

[0013] In the above preparation method, preferably, in step (1), the acid-binding agent is at least one of trimethylamine, triethylamine, tripropylamine, pyridine, potassium carbonate, sodium carbonate, sodium bicarbonate, sodium hydroxide, and potassium hydroxide, more preferably triethylamine; the organic solvent A is at least one of ethyl acetate, butyl acetate, dichloromethane, and chloroform, more preferably ethyl acetate or / and butyl acetate. In the above preparation method, preferably, in step (2), the six-membered cyclic lactide is at least one of glycolide, L-lactide, D-lactide, and racemic lactide, more preferably one or a combination of two of D-lactide and racemic lactide; compared with polyethylene glycolide, the methyl groups on the side chains of lactide after polymerization are beneficial to reducing the stereoregularity and crystallinity of the molecular chain. At the same time, the D- or racemic chiral monomers can obtain semi-crystalline or amorphous macromolecules with low glass transition temperatures after ring opening, and their faster degradation rate is more suitable for static polishing scenarios; The acrylate is at least one of methyl acrylate, ethyl acrylate, propyl acrylate, isopropyl acrylate, methyl methacrylate, ethyl methacrylate, propyl methacrylate, and isopropyl methacrylate, more preferably methyl methacrylate; the methyl group on the acrylate linkage can weaken the polymer crystallization tendency, while the sterically hindered ester group can improve the competitive polymerization activity. The catalyst is a phosphononitrile base containing 1 to 5 repeating "-P=N-" junctions in its molecular structure, more preferably containing 4 to 5 repeating "-P=N-" junctions (P4 to P5); the more "-P=N-" junctions there are, the stronger its basicity and catalytic activity. Due to the high compatibility requirements of anionic hybrid copolymerization for monomers / catalysts, a strongly basic phosphononitrile catalyst should be selected to ensure the smooth occurrence of the reaction. The initiator is at least one selected from methanol, ethanol, ethylene glycol, benzyl alcohol, ethyl acetate, and butyl acetate. The organic solvent B is at least one of toluene, xylene, and trimethylbenzene.

[0014] As part of the general inventive concept, the present invention also provides an antifouling agent system, comprising an antifouling agent and micro / nano particles, wherein the micro / nano particles have a hollow inner cavity and a mesoporous surface, and the antifouling agent is loaded within the hollow inner cavity of the micro / nano particles.

[0015] In the aforementioned antifouling agent system, preferably, the antifouling agent is one or more of the following: 4,5-dichloro-2-n-octyl-4-isothiazolin-3-one (DCOIT), pyridine triphenylborane (PTPB), zinc pyridinethione (ZnPT), 2-tert-butylamino-4-cyclopropylamino-6-methylthio-s-triazine (Irgarol 1051), 2-(p-chlorophenyl)-3-cyano-4-bromo-5-trifluoromethyl-pyrrole (Econea), zinc mancozeb, medemididine, betaine, butenolate, and their derivatives. Due to limitations in the pore size of the micro / nano particles, it is further preferred to select at least one of DCOIT, Econea, Irgarol 1051, butenolate, medemididine, and their derivatives that is soluble in organic solvents and can freely enter and exit the internal cavity in monomolecular form. ZnPT, Zineb, and PTPB generally exist in a multi-molecular aggregate state due to their limited solubility, resulting in relatively large volumes (micrometer-scale) and difficulty in penetrating narrow pores. To balance universal antifouling properties, economy, and environmental friendliness, the combination of green, low-toxicity, and inexpensive DCOIT and Econea is preferred.

[0016] In the aforementioned antifouling agent system, preferably, the micro / nanoparticles have a mesoporous hollow structure with a mesopore diameter of 2–50 nm. The micro / nanoparticles are made of transition metal oxides or non-metal oxides, including one or more of SiO2, Al2O3, TiO2, and ZrO2; the micro / nanoparticles have a tubular, barrel-shaped, cage-shaped, sandwich-like, spherical, or regular / irregular polyhedral appearance. Within the limits of the manufacturing technology, ensuring sufficient mechanical strength, and without affecting the fineness of the subsequent antifouling composition, the internal cavity of the micro / nanoparticles should be as spacious as possible to maximize the charge content.

[0017] To balance the smoothness of the antifouling agent's entry into the hollow cavity and the long-term nature of its dissolution and release, the size of the micro- and nano-sized mesopores needs to be controlled, with a preferred diameter of 2–20 nm. While narrower mesopores may help the antifouling agent dissolve slowly, they are not conducive to entry and full-load enrichment; conversely, wider mesopores may result in "more entry and more exit, and faster entry and exit".

[0018] Preferably, the antifouling agent system described above is prepared by a vacuum impregnation process.

[0019] As part of the general inventive concept, the present invention also provides a marine antifouling composition comprising the above-mentioned dual-degradable resin and the above-mentioned antifouling agent system.

[0020] The above-mentioned marine antifouling composition, preferably, comprises the following components by weight: 35-45 parts of the dual-degradable resin, 25-45 parts of the antifouling agent system, 3-8 parts of rosin, 1-3 parts of chlorinated paraffin, 0-10 parts of talc, 5-15 parts of chopped glass fiber, 0-5 parts of pigment, and 10-20 parts of xylene.

[0021] As a general inventive concept, the present invention also provides the use of the above-described dual-degradable resin or the above-described antifouling agent system in the preparation of marine antifouling compositions.

[0022] In the above applications, preferably, the marine antifouling composition is used in static marine engineering facilities such as offshore wind power, photovoltaic, ranches, beacons, floating valves, and oil and gas drilling platforms.

[0023] The main principles of this invention include: Dual-degradable resin: Traditional zinc / copper acrylate resins only undergo side-chain hydrolysis, and the polishing process heavily relies on water rinsing; the main chain generally lacks degradability, ultimately resulting in microplastic residues. This invention employs anionic hybrid copolymerization technology to integrate three monomers onto the same polymer chain: (1) Six-membered cyclic lactide, as a monomer capable of ring-opening polymerization, forms polyester segments that constitute the resin backbone after ring opening. This polyester backbone can be rapidly degraded under the action of seawater, enzymes, or microorganisms, which is the basis for achieving "water-independent" polishing. By selecting lactide with different chiralities (such as dextrorotatory or racemic forms), the stereoregularity and crystallinity of the polymer chain can be effectively reduced, forming a semi-crystalline or amorphous form with a low glass transition temperature, thereby adjusting the resin hardness, modulus, and degradation rate, making it more suitable for the rapid polishing requirements under static working conditions.

[0024] (2) Acrylates: As a conventional component (rigid segment), they provide good film-forming properties and mechanical strength. When combined with flexible six-membered cycloalloys, they enable precise control over the rate of resin degradation (polishing).

[0025] (3) Capsaicin acrylate: This invention creatively utilizes biomass capsaicin (capsaicin is derived from nature and has good inhibitory and repellent effects on harmful aquatic organisms such as bacteria, fungi, and barnacle larvae. It is also stable and temperature-insensitive) through simple esterification, which can then be used as a functional side group to participate in copolymerization. Subsequently, it can also release antifouling activity in real time during hydrolysis. This unit has three functions: First, it plays the role of "side chain hydrolysis", which further improves the resin degradation and polishing rate; second, it is a functional side group. As its ester bond breaks, capsaicin is continuously released, providing real-time and active antifouling efficacy; third, it is an intrinsic plasticizer. The introduction of the large capsaicin side group further inhibits the regular arrangement of polymer chains, weakens the crystallization tendency, helps to reduce the resin modulus, and promotes degradation.

[0026] Therefore, the resin designed in this invention can undergo dual degradation of both the main and side chains in a seawater environment, thereby achieving efficient and self-polishing, and simultaneously releasing the natural antifouling agent capsaicin. The structure of the dual-degradable resin of this invention and its simplified degradation formula are as follows: Figure 1 As shown.

[0027] In the construction of antifouling agent systems, conventional porous adsorption generally uses the natural pores of activated carbon, sepiolite, nanotubes, metal-organic frameworks, etc., as carriers. Due to the narrow pore volume, the amount of agent that can be loaded is limited. This invention cleverly selects artificial hollow mesoporous micro-nano particles as acceptor containers, with the mesopores covering their surface serving as channels for the entry and exit of the antifouling agent, and the internal cavity serving as a large-volume agent storage warehouse, which can achieve "large-capacity slow consumption" of the antifouling agent.

[0028] Compared with the prior art, the beneficial effects of the present invention are as follows: (1) By introducing biodegradable polyester segments (six-membered cyclolactone) into the resin backbone through anionic hybrid copolymerization, the resin can be autonomously degraded under the action of seawater, enzymes, or microorganisms, overcoming the technical bottleneck of traditional marine self-polishing resins where only the side chains are hydrolyzed and the backbone is difficult to degrade. This design allows the paint film to achieve active polishing through backbone breakage even without relying on water flow, effectively preventing fouling and biofouling. In addition, the capsaicin units suspended in the side chains can also be hydrolyzed and exert antifouling activity in real time. The dual-degradable resin of this invention has low hardness and fast polishing rate, meeting the special requirements of static marine engineering facilities such as offshore wind power foundations for polishing performance.

[0029] (2) Instead of using conventional porous materials (such as activated carbon and sepiolite) with limited charge capacity, innovatively using hollow mesoporous micro-nano particles with a designable structure as the antifouling agent carrier, the large internal cavity enables high-throughput loading of the antifouling agent, while the surface mesopores act as "molecular valves," ensuring both the smooth entry of single molecules of antifouling agent during loading and its slow and sustained release in the marine environment. This solves the dual problems of easy "explosive release" in traditional physical blending and low charge capacity of conventional carriers. At the same time, the selected green antifouling agents (such as DCOIT and Econea) fundamentally avoid the potential harm of heavy metals (such as tin and copper) to the marine ecosystem, which is in line with the environmental protection concept of sustainable development.

[0030] (3) The anionic hybrid copolymerization technology catalyzed by phosphononitrile base can achieve efficient copolymerization of six-membered cyclic lactones and acrylate double carbon bonds in a one-step process at room temperature. The reaction conditions are mild, no high temperature and high pressure are required, and the energy consumption is significantly lower than that of traditional multi-step synthesis methods. Furthermore, by precisely controlling the ratio of catalyst, initiator and monomer feed, it is easy to customize the polymer molecular structure. The process flow is simple and convenient for industrial-scale production.

[0031] (4) In the marine antifouling composition of the present invention, the dual-degradable resin and the antifouling agent system produce an excellent synergistic effect. The resin continuously polishes and exposes new antifouling agent particle surfaces, which, together with the capsaicin released by the resin itself, form multiple antifouling defenses. This collaborative mechanism of "degradation and polishing renewal + chemical pre-embedding + capsaicin stimulated release" provides broad-spectrum and long-lasting antifouling capabilities, effectively inhibiting the attachment and growth of various marine organisms such as bacteria, algae, and chitin, and providing a reliable guarantee for the long service life of static marine engineering facilities.

[0032] (5) The marine antifouling composition of the present invention abandons copper-based antifouling agents, which can avoid the risk of galvanic corrosion that may be induced by aluminum-copper contact, and is therefore particularly suitable for the protection of aluminum marine engineering facilities. At the same time, the spherical configuration of the antifouling agent micro-nano particles can produce a "ball effect" during coating application, which can improve the flow and leveling properties of the composition, help to form a denser and smoother paint film, and further enhance its physical barrier effect.

[0033] In summary, this invention eliminates the technical pain points of pollution prevention in static marine engineering facilities from the design source, and provides an environmentally friendly, long-lasting, and simple overall solution, which has broad application prospects in the field of static marine engineering facilities. Attached Figure Description

[0034] To more clearly explain the technical solutions in the embodiments of the present invention or the prior art, the accompanying drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the drawings in the following description are merely some embodiments of the present invention, and those skilled in the art can obtain other drawings based on these drawings without creative effort.

[0035] Figure 1 The structure of the dual-degradable resin and its simplified degradation formula are shown, in which, Figure 1 (a) Polycyclic lactone segments can degrade at a relatively fast rate in seawater, leading to the disintegration of the macromolecular backbone, thereby achieving paint film polishing and renewal, and capsaicin unit hydrolysis simultaneously releasing antifouling activity; Figure 1 (b) is a schematic diagram of the resin degradation process.

[0036] Figure 2 The FTIR spectrum of capsaicin acrylate obtained in Example 1 is shown below. Figure 2 (a) Figure 2 (b) Corresponding to capsaicin and capsaicin acrylate, respectively.

[0037] Figure 3 The dual-degradable resin 2 prepared in Example 2 1 HNMR spectrum.

[0038] Figure 4 This is the configuration of the antifouling agent system.

[0039] Figure 5 To ensure the antifouling effectiveness of the antifouling composition in shallow seas, among which, Figure 5 (a) Figure 5 (b) Figure 5 (c) Samples corresponding to Example 4, Example 5 and Comparative Example 3, respectively. Detailed Implementation

[0040] To facilitate understanding of the present invention, the present invention will be described more fully and in detail below with reference to the accompanying drawings and preferred embodiments, but the scope of protection of the present invention is not limited to the following specific embodiments.

[0041] Unless otherwise defined, all technical terms used herein have the same meaning as commonly understood by those skilled in the art. The technical terms used herein are for the purpose of describing particular embodiments only and are not intended to limit the scope of the invention.

[0042] Unless otherwise specified, all raw materials, reagents, instruments and equipment used in this invention can be purchased from the market or prepared by existing methods.

[0043] In the following examples and comparative examples, the antifouling effect of the composition was evaluated according to GB / T 5370-2007, the polishing rate was determined according to GB / T 31411-2015, and the drug loading was calculated based on the ratio of the mass difference of the micro / nano mesoporous particles before and after impregnation to the particle's own weight. The artificial seawater was prepared according to GB / T 7790-2008, section 5.1, and the release behavior of DCOIT and Econea was detected using a UV-Vis-NIR spectrophotometer. All raw materials and reagents were purchased through normal commercial channels (e.g., XFF29 hollow mesoporous SiO2 nanospheres produced by Jiangsu Xianfeng Nanomaterials Technology Co., Ltd.). The antifouling composition was coated onto a 350×250mm test plate using a wire rod roller, and the solvent evaporated to form a film.

[0044] Example 1: The dual-degradable resin 1 in this embodiment has the following structural formula:

[0045] The preparation method of the dual-degradable resin 1 in this embodiment includes the following steps: (1) Add 0.115 mol of purified capsaicin to a three-necked flask, dissolve it in 300 mL of ethyl acetate, add an equimolar amount (0.115 mol) of triethylamine, slowly add 0.1 mol of methacryloyl chloride under an ice-water bath, pass in protective N2, stir continuously for 4 h, wash 4 times with saturated NaHCO3 aqueous solution, adjust the pH value to neutral, and dry to obtain a light yellow powder.

[0046] FTIR comparison revealed that 3650cm -1 The phenolic hydroxyl peaks that were originally attributed to capsaicin disappeared at 1720 cm⁻¹. -1 1140cm -1 The newly appearing peaks correspond to the stretching vibrations of the -COO- and -C=C- bonds, respectively, indicating that capsaicin has successfully linked methacryloyl units through esterification. Its FTIR spectrum is shown below. Figure 2 .

[0047] (2) Add 0.12 mol of racemic lactide, 0.1 mol of methyl methacrylate, and 0.12 mol of capsaicin acrylate synthesized in step (1) sequentially to a three-necked flask containing 600 mL of xylene. Purge with protective N2 and stir thoroughly to ensure good dissolution of all components. Then, add 200 µL of benzyl alcohol and 2.5 mL of 0.8 M P4 phosphononitrile base-xylene solution using a micropipette. Continue the reaction at 23–25 °C for 8 h, then purify and dry to obtain the dual-degradable resin 1. The yield was calculated to be approximately 93%, and the number-average molecular weight was 19270 g / mol, the distribution index was 1.68, and the modulus was 81 MPa, as measured by GPC.

[0048] Example 2: The dual-degradable resin 2 in this embodiment has the following structural formula:

[0049] The preparation method of the dual-degradable resin 2 in this embodiment includes the following steps: (1) Add 0.105 mol of purified capsaicin to a three-necked flask, dissolve it in 300 mL of butyl acetate, add an equimolar amount (0.105 mol) of triethylamine, slowly add 0.1 mol of methacryloyl chloride in an ice-water bath, introduce protective N2, stir continuously for 6 h, wash 5 times with saturated NaHCO3 aqueous solution, adjust the pH to neutral, and dry to obtain a light yellow powder.

[0050] (2) Add 0.1 mol of dextrorotatory lactide, 0.1 mol of methyl methacrylate, and 0.105 mol of capsaicin acrylate synthesized in step (1) sequentially to a three-necked flask containing 550 mL of xylene. Introduce protective N2 and stir thoroughly to ensure good dissolution of all components. Then, add 150 µL of methanol and 2.0 mL of 0.8 M P4 phosphononitrile base-xylene solution using a micropipette. Continue the reaction at 23–25 °C for 7 h, then purify and dry to obtain the dual-degradable resin 2. The calculated yield is approximately 90.5%, with a number-average molecular weight of 16100 g / mol, a distribution index of 1.57, and a modulus of 93 MPa. 1 HNMR spectrum see Figure 3 .

[0051] Example 3: The antifouling agent system configuration in this embodiment is as follows: Figure 4 As shown, it contains antifouling agent and mesoporous hollow SiO2 micro-nanospheres.

[0052] The preparation process of the antifouling agent system in this embodiment includes: Dry mesoporous hollow SiO2 microspheres (surface mesopore diameter 2–15 nm, hollow cavity diameter 0.4–1.2 µm) were placed in a two-necked flask. Air was removed from the microspheres under vacuum. Then, a butyl acetate solution containing DCOIT and Econe (1:1) was drawn in under negative pressure and ultrasonically dispersed, allowing the antifouling agent to completely fill the internal cavity through the mesopores on the microsphere surface. After soaking at room temperature for 24 hours, excess solution was filtered off, and the microspheres were dried at room temperature for later use. The antifouling agent loading of this system was measured to be 120.1%.

[0053] Example 4: A marine antifouling composition, by weight, comprises 40 parts of the bidegradable resin prepared in Example 1, 38 parts of the antifouling agent system prepared in Example 3, 4 parts of rosin, 2 parts of chlorinated paraffin, 5 parts of talc, 8 parts of chopped glass fiber, 3 parts of iron oxide red, and 15 parts of xylene.

[0054] Example 5: A marine antifouling composition, by weight, comprises 40 parts of the dual-degradable resin prepared in Example 2, 38 parts of the antifouling agent system prepared in Example 3, 4 parts of rosin, 2 parts of chlorinated paraffin, 5 parts of talc, 8 parts of chopped glass fiber, 3 parts of iron oxide red, and 15 parts of xylene.

[0055] Comparative Example 1: A marine antifouling composition is identical to that of Example 4, except that 40 parts of commercially available 100Z type zinc acrylate resin are used instead of the dual-degradable resin 1 prepared in Example 1.

[0056] Comparative Example 2: A marine antifouling composition, except that 38 parts of Cu2O are used instead of the antifouling agent system prepared in Example 3, the other raw materials and dosages are the same as in Example 5.

[0057] Comparative Example 3: A marine antifouling composition, by weight, comprises 40 parts of commercially available 100Z type zinc acrylate resin, 38 parts of Cu2O, 4 parts of rosin, 2 parts of chlorinated paraffin, 5 parts of talc, 8 parts of chopped glass fiber, 3 parts of iron oxide red, and 15 parts of xylene.

[0058] The key properties of each marine antifouling composition are shown in Table 1 below.

[0059] Table 1. Performance of marine antifouling compositions

[0060] The comprehensive experimental data shows that by changing the feed ratio, the number of lactide chain segments in the dual-degradable resin 1 is higher than that in the dual-degradable resin 2 (i.e., more "soft segments" and lower modulus), and the racemic structure is more likely to form semi-crystalline or even amorphous states than the dextrorotatory structure, allowing resin 1 to degrade faster and achieve a slightly higher monthly polishing rate. In contrast, the zinc acrylate resin in Comparative Example 1 can only be hydrolyzed individually, and its polishing ability under low-speed water flow shear is weaker than that in Examples 4 and 5.

[0061] Thanks to the "valve" effect of the mesopores on the surface of the micro-nanospheres, the release rate of the antifouling agent was slowed down, achieving a basically "gradual" dissolution, with the average daily release maintained at 16.2–17.6 μg / cm³ over 45 days. 2 / d, coupled with an abundant internal drug storage capacity (loading rate of 120.1%), is sufficient to support its long-term and stable efficacy. Experiments revealed that, due to the lack of effective control over the Cu2O used in comparative examples 2 and 3, a relatively significant "explosive release" occurred in the mid-to-late stages (30-45 days), with a large dose of copper ions dissolving (>22 μg / cm³). 2 / d), it is foreseeable that depletion may occur over time. In addition, due to the slow hydrolysis of zinc acrylate, the surface renewal of the coating is hindered, and the release rates of Comparative Examples 1 and 3 are not as good as those of Examples 4 and 2; conversely, the release rate of Example 4 is faster than that of Example 5.

[0062] It is worth mentioning that during the dual degradation process of degradable resins 1 and 2, the capsaicin units originally locked in the lateral position were released with hydrolysis, and the antifouling effect was activated. This resulted in Examples 4 and 5 maintaining good antifouling properties even when the release levels of DCOIT and Econea were low. During the entire summer and autumn aquatic life growth season in the Qingdao sea area (February 28, 2024 to November 29, 2024), the scores reached the standard (>85), indirectly demonstrating the good synergistic effect of capsaicin and the antifouling agent. Figure 5 (a) Figure 5 As shown in (b), excluding the influence of the sample edge, only three to five barnacles are attached to the central area; in contrast, comparative example 3 has a large area of ​​mussels and barnacles growing. Figure 5 (c) The score is far below 85, indicating that the anti-fouling function has failed.

[0063] In summary, this invention utilizes a one-step anionic hybrid copolymerization method to synthesize a specific resin that exhibits both main and side chain degradation and dangling capsaicin moieties. The resin's rigidity, flexibility, and polishing rate can be controlled through molecular design and monomer material ratios. Simultaneously, by using mesoporous hollow micro / nano particles as drug carriers, the limitations of pore volume are overcome, achieving high-throughput loading (120.1%) and long-term, slow release of the antifouling agent. Marine antifouling compositions formulated based on this dual-degradable resin and antifouling agent system are suitable for static antifouling requirements in various applications, including offshore wind power, photovoltaic systems, ranches, beacons, floating valves, and oil and gas drilling platforms.

[0064] The above embodiments should be understood as being used only to more clearly illustrate the present invention, and not to limit the scope of the invention. After reading this invention, any modifications of these embodiments by those skilled in the art, inspired by it, all fall within the protection scope defined by the appended claims.

Claims

1. A marine antifouling composition, characterized in that, The system comprises a dual-degradable resin and an antifouling agent, wherein the structure of the dual-degradable resin is shown in Formula I: ， Formula I Where R1 is -H or -CH3, R2 is any one of -CH3, -CH2CH3, -CH2CH2CH3, and -CH(CH3)2, and x, y, and z are independent positive integers; The antifouling agent system includes an antifouling agent and micro / nano particles. The micro / nano particles have a hollow inner cavity and a mesoporous surface, and the antifouling agent is loaded inside the hollow inner cavity of the micro / nano particles.

2. The marine antifouling composition according to claim 1, characterized in that, The dual-degradable resin is prepared by anionic hybrid copolymerization of six-membered cyclolactone, acrylate, and capsaicin acrylate. The six-membered cyclic lactide is at least one of glycolide, L-lactide, D-lactide, and racemic lactide; The acrylate is at least one of methyl acrylate, ethyl acrylate, propyl acrylate, isopropyl acrylate, methyl methacrylate, ethyl methacrylate, propyl methacrylate, and isopropyl methacrylate. The capsaicin acrylate is prepared by esterification of capsaicin with acryloyl halide or methacryloyl halide.

3. The marine antifouling composition as described in claim 1, characterized in that, The dual-degradable resin is mainly prepared by the following method: (1) Capsaicin, organic solvent A, acid-binding agent and acryloyl halide are mixed and reacted in a protective atmosphere, washed and dried to obtain capsaicin acrylate; wherein the acryloyl halide is acryloyl chloride or methacryloyl chloride; (2) Dissolve the six-membered cyclolactone, acrylate and capsaicin acrylate obtained in step (1) in organic solvent B, add catalyst and initiator, and carry out anionic hybrid copolymerization reaction in a protective atmosphere. After the reaction is completed, purify and dry to obtain the dual-degradable resin.

4. The marine antifouling composition according to claim 3, characterized in that, In step (1), the molar ratio of capsaicin, acid-binding agent and acryloyl halide is (1.0-1.2):(1.0-1.2):1.0, the reaction temperature is 0-4℃, and the reaction time is 3-7h; In step (2), the molar ratio of six-membered cyclolactone, acrylate and capsaicin acrylate is (0.9-1.3):1.0:(1.0-1.3), and the molar ratio of initiator, catalyst and acrylate is (0.01-0.03):(0.01-0.03):1.0; the temperature of the anionic hybrid copolymerization reaction is 20-30℃, and the reaction time is 6-10h.

5. The marine antifouling composition as described in claim 3, characterized in that, In step (1), the acid-binding agent is at least one of trimethylamine, triethylamine, tripropylamine, pyridine, potassium carbonate, sodium carbonate, sodium bicarbonate, sodium hydroxide, and potassium hydroxide; the organic solvent A is at least one of ethyl acetate, butyl acetate, dichloromethane, and chloroform. In step (2), the catalyst is a phosphononitrile base containing 1 to 5 repeating "-P=N-" junctions in its molecular structure; The initiator is at least one selected from methanol, ethanol, ethylene glycol, benzyl alcohol, ethyl acetate, and butyl acetate. The organic solvent B is at least one of toluene, xylene, and trimethylbenzene.

6. The marine antifouling composition according to claim 1, characterized in that, The antifouling agent is at least one of 4,5-dichloro-2-n-octyl-4-isothiazolin-3-one, pyridine triphenylborane, zinc pyridinethione, 2-tert-butylamino-4-cyclopropylamino-6-methylthio-s-triazine, 2-(p-chlorophenyl)-3-cyano-4-bromo-5-trifluoromethyl-pyrrole, zineb, metoimidine, betaine, butenolate and its derivatives.

7. The marine antifouling composition according to claim 1, characterized in that, The micro / nanoparticles are made of transition metal oxides or non-metal oxides, and the mesopore diameter on their surface is 2–50 nm.

8. The marine antifouling composition according to claim 1, characterized in that, By weight, it comprises the following components: 35-45 parts of the dual-degradable resin, 25-45 parts of the antifouling agent system, 3-8 parts of rosin, 1-3 parts of chlorinated paraffin, 0-10 parts of talc, 5-15 parts of chopped glass fiber, 0-5 parts of pigment, and 10-20 parts of xylene.

9. The application of a marine antifouling composition as described in any one of claims 1 to 8 in static marine engineering facilities such as offshore wind power, photovoltaic, ranching, beacons, floating valves, and oil and gas drilling platforms.

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