Antifouling agent, micro-nano mesoporous material, and marine antifouling composition
Patent Information
- Authority / Receiving Office
- WO · WO
- Patent Type
- Applications
- Current Assignee / Owner
- Filing Date
- 2025-10-11
- Publication Date
- 2026-08-13
Smart Images
Figure CN2025127072_13082026_PF_FP_ABST
Abstract
Description
An antifouling agent, micro / nano-porous materials and marine antifouling composition Technical Field
[0001] This invention belongs to the field of organic-inorganic hybrid functional materials, specifically relating to an antifouling agent, micro / nano-porous materials, and marine antifouling compositions. Background Technology
[0002] Marine organisms attaching to and reproducing have serious negative impacts on marine engineering and national defense construction. They not only reduce ship speed and significantly increase fuel consumption, but can also cause instability in facilities / platforms. Their acidic secretions can also exacerbate metal corrosion. Effectively addressing marine biofouling has always been a global and enduring challenge. Among various protective measures, applying antifouling coatings is undoubtedly one of the most economical, convenient, and ideal methods.
[0003] The key component of antifouling coatings is the antifouling agent system, which should have characteristics such as low toxicity, high efficiency, broad spectrum, and long-lasting effect, so as to effectively kill as many adhering organisms as possible without damaging the marine ecosystem, while also being able to maintain its effect for a long time.
[0004] Tributyltin (TBT) was once widely used worldwide due to its excellent antifouling properties. However, it was later discovered that tin disrupts biological endocrine systems, and its metabolites have toxicity levels as high as 100–400 µg / L. Since 2008, it has been completely banned by the International Maritime Organization. 4,5-Dichloro-2-n-octyl-4-isothiazolin-3-one (DCOIT), as the first green antifouling agent registered with the EU BPD with minimal bioaccumulation (half-life ≤1h), has a metabolite toxicity >125 mg / L and an acute oral titer in rats of 100 µg / L. D 50 >2800 mg / kg, rabbit acute percutaneous L D 50 With a concentration >5000mg / kg, DCOIT boasts unparalleled environmental friendliness and versatility compared to TBT. It effectively inhibits and kills the growth of fungi (such as molds and yeasts), bacteria, algae, mucus, seagrass, sea anemones, tunicates, sponges (the so-called "soft fouling organisms"), as well as hard-shelled invertebrates such as barnacles and tube worms ("hard fouling organisms"). DCOIT and its derivatives are considered by the industry to be the top choice for current general marine antifouling agents. To achieve long-term antifouling efficacy, researchers have spared no effort in modifying it into a controlled-release system through multiple pathways.
[0005] The following patents, CN102293198B, CN101137288B, KR101253065B1, JP2008513475A, and WO2006032019A1, use DCOIT as the core material and develop water-in-oil core-shell structured microcapsules through multiple processes. They exhibit good sustained-release properties, with less than 10% release after 90 days of soaking in xylene. Zhou Yaoru (Fine and Specialty Chemicals, 2024, 32(2):39-44) also synthesized DCOIT@HACC-SA (quaternary ammonium salt chitosan-sodium alginate) microcapsules, but the initial exudation was too rapid (75.4% explosive release within 12 days), making it difficult to meet the long-term antifouling requirements of the ocean.
[0006] Besides microencapsulation, using intermolecular hydrogen bonds, van der Waals forces, electrostatic coupling, etc., to physically adsorb DCOIT onto the surface or / and internal channels of micro-nano particles with high specific surface area is also a common operation. Wang Xiaowei (Fine Chemicals, 2007, 24(10):944-947; 2007, 24(3):213-220) encapsulated DCOIT with copper microspheres and nano-titanium tubes, but the drug loading was low, with a maximum of only 15.2% and 12%, respectively. The following patents US6676954B2 and CN1229022C disclose a controlled-release composition, in which DCOIT antifouling coatings adsorbed with different activated carbons release 53% (C-1 carbon form) in artificial seawater in 21 days or 50% in only 30 days (C-2 carbon form), which is also only suitable for short-term antifouling.
[0007] Patent CN115141508B discloses a long-lasting antifouling agent supported on a metal-organic framework and its preparation method. It relies on the synergistic effect between BIT-NH2 quaternary ammonium salt and the UiO-66-COOH framework. BIT exhibits significant slow-release properties in artificial seawater, requiring 45 days and 47 days respectively for 50% release at 39.75% and 40.51% loadings. Similarly, Zhang Xin (Surface Technology, 2024, 53(8):107-118) successfully encapsulated carboxylated 1,2-benzisothiazolin-3-one (BIT-COOH) within an amino ZIF-7 (NH2-ZIF-7) nanocage using an impregnation method, achieving slow-release stability and excellent antibacterial / algae-reducing properties.
[0008] The patent with publication number CN110835495B provides a moisture-curing polyurethane antifouling coating for fishing nets and its preparation method. It uses linear hydroxyl-terminated polycaprolactone resin, which is aminated with diisocyanate and crosslinked with water vapor. The coating film can meet the flexibility requirements of fishing nets. However, the diatomaceous earth, sepiolite, and calcined kaolin porous fillers used are not modified by volume expansion or other methods. The brominated pyrrolidone and DCOIT biocide are only simply adsorbed, and the drug loading is unknown.
[0009] In general, microencapsulation and physical adsorption each have their advantages and disadvantages in sustained-release and controlled-release. The drug loading capacity of microcapsules can be adjusted by the capsule diameter, but the preparation process is relatively complex. Furthermore, simple oil-in-water or water-in-oil configurations can be swollen by organic solvents or seawater in antifouling coatings, causing capsule adhesion and rupture, leading to excessive and rapid dissolution of the antifouling agent core. Physical adsorption involves weak intermolecular forces, making the antifouling agent easily desorbed (detached from the carrier). In addition, natural porous materials (such as carbon nanotubes, halloysite, montmorillonite, zeolite, etc.) have narrow pores, mostly mesoporous (2–50 nm), with limited volume. The compatibility differences between inorganic powders and the organic film-forming resins of antifouling coatings also make the antifouling agent encapsulation system prone to sedimentation and segregation. Summary of the Invention
[0010] To address the aforementioned shortcomings, this invention aims to disclose an antifouling agent, a micro / nano-mesoporous material, and a marine antifouling composition. The micro / nano-mesoporous material matrix undergoes hydrothermal acid etching for volume expansion, resulting in the enrichment of activated silanol groups that covalently link with degradable terminal isocyanates (R-NCO) in quaternized DCOIT derivatives. This high-throughput, strong chemical bonds securely lock the organic antifouling agent guest molecules within the modified micro / nano-mesoporous material matrix, resulting in a green and environmentally friendly product with long-lasting, slow-release antifouling properties.
[0011] To achieve the above objectives, the technical solution of the present invention is as follows:
[0012] An antifouling agent with the structure of general formula I:
[0013]
[0014] Formula I
[0015] In Equation I, m and n are non-zero natural numbers, and X is a halogen.
[0016] The present invention also discloses a micro / nano-mesoporous material, comprising a micro / nano-mesoporous material matrix and the antifouling agent, wherein the activated silanol groups in the micro / nano-mesoporous material matrix are covalently linked to the -NCO units in the antifouling agent.
[0017] The aforementioned micro / nano mesoporous materials refer to materials with pore sizes between 2 and 50 nm and high specific surface areas (BET ≥ 150 nm). 2 / g), inorganic, organic, or organic-inorganic hybrid materials with good adsorption / catalytic activity and complex pore structure.
[0018] The antifouling agent is prepared by reacting a DCOIT-like derivative, a halogenated fatty alcohol, and a diisocyanate.
[0019] In a preferred embodiment of the present invention, the micro / nano-porous material matrix includes one or more of sepiolite, halloysite, montmorillonite, zeolite, fumed silica, and organometallic frameworks.
[0020] In a preferred embodiment of the present invention, the micro-nano mesoporous material matrix is sepiolite, and the structure of the micro-nano mesoporous material is shown in Figure 1.
[0021] In Figure 1, the hollow tube represents the porous fiber 1 of sepiolite, and the black curve represents the long chain of antifouling agent 2 chemically loaded with active silanol groups on the surface and inside of sepiolite.
[0022] In a preferred embodiment of the present invention, when the micro / nano-mesoporous material matrix is sepiolite, the particle size of the micro / nano-mesoporous material matrix is 200–3000 mesh. Preferably, the particle size of the micro / nano-mesoporous material matrix is 800–2000 mesh. Within this particle size range, sepiolite fibers have regular morphology, good adjustability of drug loading, and high compatibility with the antifouling composition.
[0023] In a preferred embodiment of the present invention, the preparation method of the micro / nano-mesoporous material includes the following steps: S1, the micro / nano-mesoporous material matrix is subjected to hydrothermal acid etching, washing, calcination, and then cooled for later use; S2, a DCOIT-like derivative and a halo-fatty alcohol are dissolved in a solvent, heated under reflux, and then a mixture of diisocyanate and catalyst is added dropwise, and the reaction is continued at a constant temperature; S3, the micro / nano-mesoporous material modified matrix obtained in S1 is ground and dispersed in a solvent, added to the S2 system and heated to react, and then purified, dried, ground, and stored.
[0024] In a preferred embodiment of the present invention, the acid etching in step S1 uses 8-10 wt% dilute hydrochloric acid. Preferably, the micro / nano-mesoporous material matrix is dispersed in dilute hydrochloric acid to form a suspension with 3-5 wt% solids content, and is magnetically stirred at 50-60°C for 10-12 hours. The calcination temperature is 200-300°C, and the calcination time is 1-2 hours. The washing step uses a saturated NaHCO3 solution to wash until neutral.
[0025] The molar ratio of the DCOIT-like derivative, haloalcohol, and diisocyanate in S2 is 1:(1-1.1):(1.1-1.15). Preferably, the DCOIT-like derivative, haloalcohol, diisocyanate, and solvent are all pre-dried to remove water, and the reaction is carried out under N2 atmosphere with continuous stirring throughout. More preferably, a quaternization catalyst, including one or a combination of NaI and KI, is also added to S2, and the molar ratio of the DCOIT-like derivative to the quaternization catalyst is 40-60 mmol:(40-60) mg.
[0026] Preferably, in S2, the reflux temperature is 40-50°C, the reflux time is 10-12 hours, and the subsequent heat preservation time is 6-8 hours.
[0027] Preferably, the heating temperature in S3 is 60-70°C, and the reaction time is 5-6 hours.
[0028] In a preferred embodiment of the present invention, the structure of the DCOIT-like derivative is as shown in general formula II:
[0029]
[0030] Formula II
[0031] In Formula II, R1 and R2 are independently derived from -H, -Cl, -Br, and -I, respectively; R3 is derived from any one of -H, aliphatic alkyl, aralkyl, alkoxy, alkenyl, and alkynyl. Preferably, R1 and R2 are both -Cl, and R3 is -C8H. 17 .
[0032] DCOIT-like derivatives include DCOIT and its derivatives.
[0033] DCOIT and its derivatives exhibit strong penetrability to biological cell membranes and cell walls, interacting with intracellular sulfur-containing proteins, enzymes, or active small molecules (SN bond breakage, forming SS bond), thereby disrupting cell division and proliferation. Comparative analysis revealed that the presence of large-volume substituents (such as benzene rings or long-chain aliphatic alkanes) or electron-withdrawing groups (ether bonds, carbonyl groups) on the nitrogen atom, or a higher number of halogen atoms on the isothiazolinone ring, indicates relatively stronger biological activity. Based on this, and considering factors such as market availability and price, it is preferable that R1 and R2 are both -Cl, and R3 is -C8H. 17 .
[0034] In a preferred embodiment of the present invention, the halogenated fatty alcohol includes one or more of chlorinated, brominated, and iodinated fatty alcohols containing 1 to 8 carbon atoms;
[0035] The diisocyanate is an α,ω-terminated diisocyanate fatty acid ester and its derivatives, including one or more of 2,3-diisocyanate propionate, 2,4-diisocyanate butyrate, 2,5-diisocyanate valerate, 2,6-diisocyanate hexanoate, 2,7-diisocyanate heptanoate, 2,8-diisocyanate octanoate, 2,9-diisocyanate nonanoate, 2,10-diisocyanate decanoate and their derivatives.
[0036] Considering factors such as the reactivity, price, and ease of degradation of halogenated products, the halogenated fatty alcohol is preferably 6-bromo-1-hexanol; the diisocyanate is preferably one or a combination of two of ethyl 2,5-diisocyanopentanoate and ethyl 2,6-diisocyanohexanoate.
[0037] Ethyl 2,5-diisocyanate valerate and ethyl 2,6-diisocyanate hexanoate are modified ornithine and lysine, respectively. Both are green and renewable, commercially available, and have moderate molecular chain lengths that are completely biodegradable. Other non-natural forms of diisocyanates, such as toluene diisocyanate, diphenylmethane diisocyanate, and hexamethylene diisocyanate units selected in patent publication number CN110835495B, are non-biodegradable and ultimately only decompose into "microplastics" (the degradation described in this patent essentially only occurs at the polycaprolactone segment), and their environmental friendliness needs improvement.
[0038] The solvents used in S2 and S3 are one or more of ethyl acetate, xylene, methanol, chloroform, acetonitrile, and butyl acetate.
[0039] The catalyst in S2 is one or both of diisobutyltin dilaurate and stannous isooctanoate.
[0040] In S3, the modified matrix of micro / nano-mesoporous material prepared in S1 is ground and expanded to fully loosen the aggregated fiber bundles. Then, it is ultrasonically dispersed in a solvent to facilitate the deep penetration of the solvent and reactive molecules into its interior.
[0041] The present invention also discloses a marine antifouling composition, comprising, by weight, 10-30 parts of the aforementioned micro / nano-porous material, 25-45 parts of cuprous oxide, 5-10 parts of zinc pyridinethione, 30-40 parts of hyperbranched zinc resin, 3-5 parts of modified rosin, 1-3 parts of polyethylene wax, 0-3 parts of chlorinated paraffin, 0-10 parts of filler, 0-3 parts of iron oxide red, and 10-20 parts of organic solvent.
[0042] Preferably, in the marine antifouling composition, the filler is selected from one or more of talc, titanium dioxide, silica powder, and calcium carbonate powder; the organic solvent is a mixture of xylene and n-butanol in a mass ratio of (1-3):1.
[0043] Compared to the patent with publication number CN110835495B, this solution involves the biocide physically adsorbed into the porous filler via weak interactions such as hydrogen bonding. The terminal isocyanate-based polyester resin is cured by moisture to form a film, which can be slowly hydrolyzed, releasing the antifouling agent within the coating. This invention uses a micro / nano-mesoporous material modified matrix and a DCOIT-like derivative to form a covalent link via a urethane reaction. The DCOIT-like derivative is a quaternized DCOIT-like derivative, thereby firmly encapsulating the organic antifouling agent guest molecules within the micro / nano-mesoporous material modified matrix through strong chemical bonds. This binding principle is significantly different from that of the patent with publication number CN110835495B. Furthermore, the filler involved in the patent with publication number CN110835495B was not subjected to volume expansion treatment and there is no chemical bond between it and the biocide molecules; therefore, its drug loading, actual drug release stability, and long-term effect (after 6 months) are unknown.
[0044] The following is a further explanation of the preparation mechanism of micro / nano porous materials:
[0045] Sepiolite, a representative micro / nano-mesoporous material matrix, possesses a large specific surface area and complex pores, exhibiting high dispersibility in most solvents. It is an invaluable natural load-bearing container, but unfortunately, its pore size is generally small, resulting in limited pore volume. The S1 step hydrothermal acid etching treatment further expands and extends the original cavity structure of sepiolite to increase its loading capacity. Simultaneously, it removes impurities such as calcite and quartz, effectively reducing the density of magnesium-rich silicate crystals, transforming the fibers from a bundled state to a divergent state, and obtaining more and more activated silanol groups (such as Mg in the "-Si-O-Mg-O-Si-" framework). 2+ H + (Substitution, forming Si-OH bonds). High-temperature calcination (<300℃) not only helps remove water molecules (such as adsorbed free water) existing in various forms within the sepiolite crystal lattice, avoiding the potential for the latter to terminate the -NCO chain reaction, but also increases the specific surface area and pore size of the fibers. However, it should be noted that excessively high hydrochloric acid concentrations (>15wt%) can easily cause severe fiber breakage; calcination at >300℃ may cause pore collapse, loss of hydroxyl water (meaning it no longer possesses graftability), and even a complete change in crystal form.
[0046] Studies have confirmed that the numerous silanol groups on the surface and inside of sepiolite have a strong affinity for organic matter (especially after acid etching and activation), and can be polyurethaneized with -NCO functional groups; while the N atom on the tertiary amine of the DCOIT-like derivative contains a lone pair of electrons, which can be nucleophilically replaced by a highly electronegative halogen. Based on this, the DCOIT-like derivative is quaternized into a haloalcohol salt, and after being incorporated with a specific diisocyanate, it is endowed with an active site that can covalently bond with the modified sepiolite, so that the two ultimately form a chemical loading mode that is significantly different from physical coupling such as intermolecular hydrogen bonds and electrostatic forces; subsequently, through the dual degradation of amino acid esters and fatty alcohol units in the polyurethane chain, the antifouling agent is slowly released, thereby exerting its efficacy.
[0047] Compared with the prior art, the beneficial effects of the present invention are as follows:
[0048] I. By covalently linking the abundant and activated silanol groups in modified sepiolite fibers with the terminal -NCO groups in the quaternary ammonium salts of DCOIT-like derivatives, antifouling agent guest molecules are locked within the acceptor container through strong chemical bonds. This provides a feasible reference for the high-value-added utilization of inorganic powders and the high-throughput loading of marine antifouling agents. Simultaneously, the compatibility between inorganic powders and film-forming resins is improved after organic hybridization, making them less prone to delamination in the composition. Other micro / nano-mesoporous material matrices rich in graftable groups such as halloysite, montmorillonite, zeolite, fumed silica, and organometallic frameworks can be modified using similar processes. The resulting organic-inorganic hybrid system is far more robust than weak interactions relying on intermolecular hydrogen bonds, van der Waals forces, and electrostatic coupling, making guest molecules less susceptible to accidental detachment (desorption) due to external stimuli such as sudden changes in temperature, concentration, or pressure. The specially selected "bridging" unit (i.e., the connecting segment between the DCOIT-like derivative and the sepiolite fiber) has a high degree of molecular rotational freedom (good flexibility) and possesses dual degradation characteristics (both diisocyanate and fatty alcohol can be completely degraded). After gradually disintegrating in the natural environment, the antifouling agent is "unlocked," allowing for slow and continuous drug release. It is worth mentioning that the organic-inorganic hybrid "comb" configuration (sepiolite fiber as the "comb handle" and the long chain of antifouling agent as the "comb teeth") can easily achieve more "comb teeth" by adjusting the size of the "comb handle" (selecting fibers with a large aspect ratio) (indicating a larger drug loading).
[0049] II. The preparation process of micro / nano-mesoporous materials is simple (significantly superior to microencapsulation), with mild reaction conditions, and can be obtained in a "one-pot" process. The hyperbranched zinc resin in the composition can self-polish, and its shedding under water rinsing can also play a secondary role in the slow release of antifouling agents. The combination of cuprous oxide and zinc pyrithione further enhances and expands the broad spectrum of biocidal activity of DCOIT-like derivatives.
[0050] Based on this, the antifouling agent, the micro / nano-mesoporous material and the marine antifouling composition prepared therefrom can encapsulate organic antifouling agent guest molecules in a high-throughput, high-efficiency micro / nano-mesoporous material modified matrix through strong chemical bonds. It has the properties of high efficiency, universality, low toxicity and long-lasting effect, and can meet the antifouling needs of multiple scenarios such as moving ships, marine ranches and static platforms. Attached Figure Description
[0051] Figure 1 is a schematic diagram of the micro-nano mesoporous material structure obtained in Example 1 or 2, wherein 1 is a porous fiber of sepiolite and 2 is a long chain of antifouling agent chemically loaded with active silanol groups on the surface and inside of sepiolite.
[0052] Figure 2 shows the micro / nano-mesoporous material prepared in Example 1. 1 HNMR spectrum.
[0053] Figure 3 shows the antifouling agent loading (TGA) in the micro / nano-mesoporous material prepared in Example 1.
[0054] Figure 4 shows the SEM images of sepiolite fibers before and after chemical loading of antifouling agent in Example 1. Figure 4(a) shows the SEM image of sepiolite fibers before chemical loading of antifouling agent, and Figure 4(b) shows the SEM image of sepiolite fibers after chemical loading of antifouling agent.
[0055] Figure 5 shows the dissolution rate of the antifouling agent in artificial seawater in the micro-nano mesoporous materials prepared in Example 1 and Comparative Example 4.
[0056] Figure 6 shows the antifouling effect of the marine antifouling compositions of Example 3 and Comparative Example 5 in shallow sea. Figure 6(a) is a photo of the sample sprayed with the marine antifouling composition of Example 3 after 2 months in the sea. Figure 6(b) is a photo of the sample sprayed with the marine antifouling composition of Example 3 after 9 months in the sea. Figure 6(c) is a photo of the sample sprayed with the marine antifouling composition of Comparative Example 5 after 2 months in the sea. Figure 6(d) is a photo of the sample sprayed with the marine antifouling composition of Comparative Example 5 after 9 months in the sea. Detailed Implementation
[0057] The present invention will be described in more detail below with reference to the accompanying drawings and embodiments. Without conflict, the embodiments and features of the present invention can be combined or modified with each other.
[0058] Artificial seawater was prepared according to the standard "Determination of Cathodic Disbondment Resistance of Coatings Exposed to Seawater for Paints and Varnishes (GB / T 7790-2008)". The release rate of DCOIT in the seawater was determined using a UV-Vis-NIR spectrophotometer. The antifouling effect in shallow seas was evaluated according to the standard "Test Method for Shallow Sea Immersion of Antifouling Paint Samples (GB / T 5370-2007)". All raw materials and reagents were purchased through normal commercial channels and were strictly dried before use, with the water content controlled to be no higher than 200 ppm. Example 1
[0059] The preparation steps of micro / nano-porous materials are as follows:
[0060] S1. Take 80g of sepiolite fiber and ultrasonically disperse it in 2000mL of 10wt% dilute hydrochloric acid aqueous solution. Stir magnetically at 60℃ for 12h, then wash with saturated NaHCO3 solution until neutral, and then transfer it to a muffle furnace for calcination at 250℃ for 1.5h. Cool and set aside for use.
[0061] S2. Dissolve 50 mmol DCOIT and 55 mmol 6-bromo-1-hexanol in 300 mL butyl acetate, then add 50 mg KI, reflux at 50 °C for 10 h, then slowly add a mixture of 57.5 mmol ethyl 2,6-diisocyanate hexanoate and 52 mg T-12, and continue the reaction at this temperature for 8 h under a N2 atmosphere throughout.
[0062] S3. Grind and sieve the modified sepiolite fiber obtained in S1, take 27g of 800-mesh powder, ultrasonically disperse it in 300mL of butyl acetate, and then add it to the S2 system. Heat to 70℃ and stir continuously for 5h under N2 atmosphere protection throughout the process. Finally, after impurity removal, purification, drying, grinding and storage, the structure of the obtained micro-nano mesoporous material is shown in Figure 1. Example 2
[0063] The preparation steps of micro / nano-porous materials are as follows:
[0064] S1. Take 100g of sepiolite fiber and ultrasonically disperse it in 2000mL of 8wt% dilute hydrochloric acid aqueous solution. Stir magnetically at 50℃ for 10h, then wash with saturated NaHCO3 solution until neutral, and then transfer it to a muffle furnace for calcination at 200℃ for 2h. Cool and set aside for use.
[0065] S2. Dissolve 50 mmol DCOIT and 55 mmol 6-bromo-1-hexanol in 250 mL ethyl acetate, then add 50 mg NaI, reflux at 45 °C for 12 h, then slowly add a mixture of 55 mmol ethyl 2,5-diisocyanate valerate and 45 mg T-12, and continue the reaction at this temperature for 7 h under a N2 atmosphere throughout.
[0066] S3. Grind and sieve the modified sepiolite fiber obtained in S1. Take 25g of 2000-mesh powder, ultrasonically disperse it in 250mL of ethyl acetate, and then add it to the S2 system. Heat to 65℃ and stir continuously for 6h under N2 atmosphere protection throughout the process. Finally, remove impurities, purify, dry, grind and store. Example 3
[0067] A marine antifouling composition, by weight, contains 15 parts of the micro / nano-mesoporous material described in Example 1, 25 parts of cuprous oxide, 6 parts of zinc pyridinethione, 35 parts of hyperbranched zinc resin, 3 parts of modified rosin, 2 parts of polyethylene wax, 1 part of chlorinated paraffin, 8 parts of talc, 1 part of iron oxide red, 10 parts of xylene, and 5 parts of n-butanol. Example 4
[0068] A marine antifouling composition, by weight, contains 20 parts of the micro / nano-porous material described in Example 2, 25 parts of cuprous oxide, 4 parts of zinc pyridinethione, 38 parts of hyperbranched zinc resin, 2 parts of modified rosin, 3 parts of polyethylene wax, 2 parts of chlorinated paraffin, 10 parts of talc, 12 parts of xylene, and 6 parts of n-butanol.
[0069] Comparative Example 1
[0070] The preparation steps of micro / nano-porous materials are as follows:
[0071] S1. Dissolve 50 mmol DCOIT and 55 mmol 6-bromo-1-hexanol in 300 mL butyl acetate, then add 50 mg KI, reflux at 50 °C for 10 h, then slowly add a mixture of 57.5 mmol ethyl 2,6-diisocyanate hexanoate and 52 mg T-12, and continue the reaction at this temperature for 8 h under a N2 atmosphere throughout.
[0072] S2. After vacuum drying the sepiolite fiber at 105℃ for 2 hours, 27g of powder with a mesh size of about 800 mesh was sieved, ultrasonically dispersed in 300mL of butyl acetate, and then added to the S1 system. The temperature was raised to 70℃ and stirred continuously for 5 hours under N2 atmosphere protection throughout the process. Finally, the powder was purified, dried, ground and stored.
[0073] Comparative Example 2
[0074] 4g of sepiolite fiber was ultrasonically dispersed in 100mL of 20wt% hydrochloric acid aqueous solution, magnetically stirred at 60℃ for 12h, and then washed with saturated NaHCO3 solution until neutral before sampling to observe fiber morphology.
[0075] Comparative Example 3
[0076] 4g of sepiolite fiber was ultrasonically dispersed in 100mL of 10wt% dilute hydrochloric acid aqueous solution, magnetically stirred at 60℃ for 12h, then washed with saturated NaHCO3 solution until neutral, and then transferred to a muffle furnace for calcination at 400-500℃ for 2h. After cooling, samples were taken to observe the fiber morphology.
[0077] Comparative Example 4
[0078] The preparation steps of micro / nano-porous materials are as follows:
[0079] Without any pretreatment, 27g of approximately 800-mesh sepiolite fiber powder was directly taken, ultrasonically dispersed in 300mL of butyl acetate containing 50mmol DCOIT, soaked at room temperature for 48h, and then dried for later use.
[0080] Comparative Example 5
[0081] A marine antifouling composition, except that it uses the micro-nano mesoporous material prepared in Comparative Example 4, uses the same raw materials and dosages as in Example 3.
[0082] Analysis shows that the FT-IR spectrum of the product obtained in Example 1 has a peak at 3460 cm⁻¹. -1 Although the Si-OH peak at 840 cm⁻¹, belonging to modified sepiolite, was significantly weakened compared to before polyurethane treatment, it was still present, indicating that there is reaction redundancy in the silanol groups. -1 A C-Cl peak appears on the isothiazolinone ring at 2260 cm⁻¹. -1The -NCO peaks associated with ethyl 2,6-diisocyanohexanoate are significantly weakened after step S2 and almost disappear after step S3, at 1640 cm⁻¹. -1 1560cm -1 A new -NHCOO- peak was added nearby, at 1100cm. -1 800cm -1 The newly added Si-OCO- bond stretching vibration peaks indicate that DCOIT has been successfully covalently grafted with sepiolite fibers through polyurethane crosslinking units (Figure 2). 1 HNMR spectroscopy can also corroborate this.
[0083] Thermogravimetric analysis (TGA) (as shown in Figure 3) revealed that the heat resistance of grafted DCOIT was improved, and the drug loading of the fiber reached 60.6% (higher than the patent with publication number CN115141508B), achieving high-throughput loading. Compared with concentration enrichment detection such as dialysis dissolution, thermogravimetric analysis can more accurately and intuitively reflect the weight loss at various temperature stages, eliminating the influence of some guest molecules entering the acceptor pores through physical adsorption, which leads to distortion of chemical drug loading data (mainly manifested as being too high). (The strength of intermolecular interactions can have a stress response to different temperatures; physical adsorption forces are weak, and desorption and weight loss occur in the low-temperature region, making it easy to identify and distinguish.)
[0084] Furthermore, SEM showed that the sepiolite used in Example 1, after S1 acid etching and calcination, had intact and relatively loose fiber morphology (even broken into monofilaments), a smooth surface, and a length exceeding 4 μm (as shown in Figure 4a). After step S3, the fiber surface roughness increased (as shown in Figure 4b), and was covered with dot-like protrusions, which further confirmed the successful linking of DCOIT.
[0085] The peak shifts of the synthesized product in Example 2 in the FT-IR spectrum were basically the same as those in Example 1. The drug loading measured by TGA was 54.8%, which may be due to the relatively short and thick modified sepiolite fibers used (2000 mesh), resulting in a slightly lower loading of the long chain of the "comb"-shaped antifouling agent.
[0086] Correspondingly, if sepiolite is not treated beforehand, as in Comparative Example 1, the fibrous crystals are dense, with few intrinsic silanol groups and low activity in the shallow and internal cavities. In addition, the free water is not completely calcined, resulting in the worthless consumption of -NCO groups. The number of polyurethane units "bridging" is limited, and a large number of DCOIT quaternary ammonium alkoxides fail to covalently bond to the sepiolite molecules, resulting in a chemical drug loading of less than 30%. During TGA testing, a large proportion of abnormal burn-off occurred in the low-temperature region (similar to Comparative Example 4), which also reflects that the guest molecules are still mostly coupled in the form of physical adsorption.
[0087] To investigate the effects of hydrochloric acid concentration and calcination temperature in step S1 on the pore structure of sepiolite, we designed comparative examples 2 and 3. SEM images showed that when the hydrochloric acid concentration increased from 15% to 20wt%, the fibers began to exhibit a decrease in specific surface area, pore blockage, and fiber breakage. Furthermore, when calcined above 400℃, the water of crystallization (and even hydroxyl water) in the fibers continuously disappeared, and the pores gradually collapsed.
[0088] As can be seen from Figure 5, in Example 1, the release of DCOIT in artificial seawater stabilized after approximately 14 days, and then exhibited a gradual dissolution (almost constant rate) over the subsequent 98 days. The dual degradation process of the polyurethane covalent bridging sites and the self-polishing of the hyperbranched zinc resin effectively regulated the slow release through a "lock-in → unlock" mechanism. In Comparative Example 4, the weak intermolecular forces were insufficient to support long-term DCOIT loading within the receptor pores (stable range 14–49 days). With prolonged immersion time, the release showed a significant increase after 50 days. It is easy to foresee that at this rate, the drug supply will soon be exhausted.
[0089] Figure 6 clearly shows the difference in antifouling performance in a certain sea area of the South China Sea after the marine antifouling compositions of Example 3 and Comparative Example 5 were applied to the samples. After more than 9 months of vigorous marine life reproduction during the summer and autumn seasons, the coating surface of Example 3 was smooth, and the influence of the edge effect of the sample was eliminated, with few species climbing in the central area (as shown in Figure 6b). In contrast, Comparative Example 5 had a large number of barnacles and mussels growing, occupying nearly 1 / 3 of the area (as shown in Figure 6d). In fact, the biocidal effect of Comparative Example 5 was not significantly different from that of Example 3 in the first two months (Figure 6c vs. Figure 6a). However, due to the different antifouling agent systems, DCOIT in Comparative Example 5 could not be restricted by sepiolite for a long time due to physical adsorption, and it gradually depleted after a certain period of time. Thanks to the strong chemical bonding, the antifouling system of Example 3 had a "zero-level" drug release function. After the "bridge" connecting the sepiolite fibers slowly disintegrated, DCOIT was gradually "unlocked", thus exerting a long-term effect.
[0090] In summary, through simple hydrothermal acid etching, quaternization, and silanol amino esterification, DCOIT-like derivative guest molecules were securely encapsulated within sepiolite acceptor containers, providing a valuable reference for the advanced utilization of inorganic powders and the high-throughput chemical loading (60.6%) of marine antifouling agents. Other micro / nano-mesoporous material matrices rich in active hydroxyl and amino groups, such as halloysite, montmorillonite, zeolite, fumed silica, and organometallic frameworks, can be modified in a similar manner. The marine antifouling composition prepared using this organic-inorganic hybrid slow-release system exhibits good compatibility among its components, high efficiency, broad spectrum, low toxicity, and long-lasting effects, making it suitable for antifouling needs in various scenarios, including mobile vessels, marine ranches, and static platforms.
[0091] 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 stain repellent, characterized in that, It contains the following molecular structure: ； The method for preparing the antifouling agent includes the following steps: The DCOIT-like derivative and the halo-fatty alcohol were dissolved in a solvent, heated to reflux, and then a mixture of diisocyanate and catalyst was added dropwise, and the reaction was continued at the temperature. The structure of the DCOIT-like derivative is as shown in Formula II: ； In formula II, R1 and R2 are both -Cl; R3 is -C8H 17 ; The halogenated fatty alcohols are chlorinated, brominated, or iodinated fatty alcohols with 1 to 8 carbon atoms; The diisocyanate is 2,3-diisocyanopropionate, 2,4-diisocyanobutyrate, 2,5-diisocyanovalerate, 2,6-diisocyanohexanoate, 2,7-diisocyanoheptanoate, 2,8-diisocyanooctanoate, 2,9-diisocyanononanoate, or 2,10-diisocyanodecanoate.
2. A micro / nano-porous material, characterized in that, The product comprises a micro / nano-mesoporous material matrix and the antifouling agent as described in claim 1, wherein the activated silanol groups in the micro / nano-mesoporous material matrix are covalently linked to the -NCO units in the antifouling agent.
3. The micro / nano mesoporous material according to claim 2, characterized in that, The micro / nano mesoporous material matrix includes one or more of sepiolite, halloysite, montmorillonite, zeolite, fumed silica, and organometallic frameworks.
4. The micro / nano mesoporous material according to claim 3, characterized in that, When the micro-nano mesoporous material matrix is sepiolite, the particle size of the micro-nano mesoporous material matrix is 200-3000 mesh.
5. The micro / nano mesoporous material according to any one of claims 2 to 4, characterized in that, The method for preparing the micro / nano mesoporous material includes the following steps: S1. The micro / nano mesoporous material substrate is sequentially subjected to hydrothermal acid etching, cleaning, calcination, and then cooled for later use. S2. Dissolve the DCOIT-like derivative and the halo-fatty alcohol in a solvent, heat under reflux, and then add a mixture of diisocyanate and catalyst dropwise, and continue the reaction at the temperature. S3. Grind and disperse the modified micro / nano mesoporous material matrix obtained in S1 in a solvent, add it to the S2 system and heat it to react. Then, after purification, drying, grinding and storage, the matrix is stored. The structure of the DCOIT-like derivative is as shown in Formula II: ； In formula II, R1 and R2 are both -Cl; R3 is -C8H 17 ; The halogenated fatty alcohols are chlorinated, brominated, or iodinated fatty alcohols with 1 to 8 carbon atoms; The diisocyanate is 2,3-diisocyanopropionate, 2,4-diisocyanobutyrate, 2,5-diisocyanovalerate, 2,6-diisocyanohexanoate, 2,7-diisocyanoheptanoate, 2,8-diisocyanooctanoate, 2,9-diisocyanononanoate, or 2,10-diisocyanodecanoate.
6. A marine antifouling composition, characterized in that, Based on weight, the material comprises 10-30 parts of the micro / nano-mesoporous material as described in any one of claims 2-5, and further comprises 25-45 parts of cuprous oxide, 5-10 parts of zinc pyridinethione, 30-40 parts of hyperbranched zinc resin, 3-5 parts of modified rosin, 1-3 parts of polyethylene wax, 0-3 parts of chlorinated paraffin, 0-10 parts of filler, 0-3 parts of iron oxide red, and 10-20 parts of organic solvent.