Silicone oil slow-release antifouling coating as well as preparation method and application thereof

Abstract

The invention relates to the technical field of antifouling coatings, in particular to a silicone oil slow-release antifouling coating as well as a preparation method and application thereof. The preparation method comprises the following steps: selecting a porous titanium silicalite molecular sieve TS-1 as a core carrier, and adsorbing dimethyl silicone oil into pores of the porous titanium silicalite molecular sieve TS-1 to prepare a silicone oil-coated TS-1 functional filler, so that the silicone oil is converted into a bound state from a free state, and the release of the silicone oil is effectively controlled; then, the functional filler is introduced into a polyurethane matrix according to the proportion of 3-8 wt%. According to the obtained coating, the long-acting antifouling function is achieved, the tensile strength is greatly improved to 3.5 MPa or above from about 1.38 MPa of pure polyurethane, and the problem of cooperation of high strength and long service life in the environment-friendly antifouling coating is successfully solved.

Description

Technical Field

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

[0002] Marine biofouling is one of the major challenges facing marine engineering equipment. It significantly increases navigation drag and energy consumption, accelerates material corrosion, and threatens facility safety. Traditional chemical antifouling coatings are being strictly limited due to their ecotoxicity, making environmentally friendly physical antifouling technologies a focus of research and development. Among them, the biomimetic liquid-permeable smooth surface (SLIPS) technology, inspired by nature, forms a molecularly smooth, low-surface-energy interface by locking a layer of lubricant (such as silicone oil) onto the designed surface, making it difficult for marine organisms to adhere firmly, and showing great application potential.

[0003] However, SLIPS technology faces the challenge of simultaneously achieving long-term stability of the lubricant and robust durability of the coating itself. To achieve long-term antifouling performance, the coating must act as an oil reservoir, holding sufficient silicone oil and allowing for slow, controlled replenishment. Current mainstream methods, such as directly physical blending low surface energy liquids with resins like polydimethylsiloxane (PDMS) or injecting them into pre-prepared porous networks, all have inherent drawbacks. Because silicone oil differs significantly from most polymer matrices in chemical polarity and molecular structure, simple blending easily leads to severe phase separation. Under the continuous shearing and scouring of dynamic seawater, silicone oil is rapidly and disorderly released from the matrix, causing the surface lubricant layer to deplete quickly and resulting in a sharp decline in antifouling performance.

[0004] To enhance oil storage capacity, a common approach is to actively construct a more porous matrix structure, but this usually comes at the cost of mechanical properties. Such coatings often exhibit poor tensile strength, modulus, and abrasion resistance, and are easily damaged during installation or when subjected to wave impacts. Their structural durability cannot meet the requirements for long-term use in harsh marine environments.

[0005] In recent years, researchers have attempted to introduce porous micro / nano particles (such as mesoporous silica) as carriers for silicone oil, hoping to bind the silicone oil through physical adsorption, improve its compatibility with the matrix, and regulate its release. However, many conventional porous inorganic fillers have weak interfacial bonding with organic polymer matrices, which can easily become stress defect points in composite materials. Instead of enhancing the coating, they may lead to decreased coating toughness, increased brittleness, and damage to its overall mechanical integrity.

[0006] Therefore, it is of great significance to develop a new type of composite antifouling coating that can achieve quantitative improvement in key mechanical properties such as tensile strength while obtaining excellent antifouling performance. Summary of the Invention

[0007] The purpose of this invention is to overcome the problems in existing biomimetic liquid-permeable smooth surface antifouling coatings, such as the difficulty in achieving both long-term stability of the lubricant and the durability of the coating itself, as well as the problem that using conventional porous fillers as carriers often damages the mechanical integrity of the coating. This invention provides a silicone oil slow-release antifouling coating, its preparation method, and its application.

[0008] The first aspect of the present invention provides a silicone oil slow-release antifouling coating, which is a polyurethane composite coating containing a functional filler dispersed in a polyurethane matrix. The functional filler is silicone oil@TS-1 formed by loading dimethyl silicone oil into the channels of a porous titanium silica molecular sieve TS-1. The functional filler accounts for 3-8 wt% of the coating by mass.

[0009] This invention provides a silicone oil slow-release antifouling coating. By selecting a porous titanium-silicon molecular sieve (TS-1) with both regular nanopores and titanium active centers as the core carrier, dimethyl silicone oil with a viscosity of 50-100 cst is fully adsorbed into its pores, resulting in a functional filler with a silicone oil loading of 30-50 wt%. Free silicone oil is transformed into a pore-bound state, effectively improving the problem of rapid release of silicone oil due to incompatibility. Subsequently, this functional filler is introduced into a polyurethane matrix at a specific ratio of 3-8 wt%, effectively ensuring sufficient filler amount to construct a continuous slow-release network and avoiding damage to the matrix continuity caused by excessive addition. The rigid TS-1 skeleton, as a nano-reinforcing phase, promotes interfacial bonding with polyurethane due to its surface properties, helping to overcome the disadvantage of ordinary inorganic fillers easily acting as stress defect points. The obtained coating not only achieves long-lasting antifouling function based on capillary binding and slow replenishment, but its tensile strength is also significantly improved by more than 20% compared to the same polyurethane coating without filler, achieving significant progress.

[0010] Furthermore, the porous titanium-silicon molecular sieve TS-1 can be synthesized by hydrothermal method, or a commercially available TS-1 product that meets the silicon-to-titanium ratio (Si / Ti=30-50) requirement of this invention can be used.

[0011] Furthermore, the polyurethane matrix described in this invention can be any type of polyurethane commonly found in the art, including but not limited to polyurethanes obtained by reacting polyether polyols, polyester polyols, etc., with diisocyanates (such as toluene diisocyanate TDI, diphenylmethane diisocyanate MDI, isophorone diisocyanate IPDI, etc.). Preferably, a polyether-type polyurethane with good flexibility and excellent hydrolysis resistance is used, such as the polytetrahydrofuran ether diol (PTMG) and IPDI system used in this embodiment.

[0012] Furthermore, in the silicone oil@TS-1 functional filler, the loading of silicone oil is 30-50 wt%.

[0013] Furthermore, the viscosity of the dimethyl silicone oil is 50-100 cst.

[0014] Furthermore, the molar ratio (Si / Ti) of silicon to titanium in the porous titanium-silicon molecular sieve TS-1 is 30-50.

[0015] A second aspect of the present invention provides a method for preparing the above-mentioned silicone oil slow-release antifouling coating, comprising the following steps: S1. Preparation of functional filler: The porous titanium silica molecular sieve TS-1 is immersed in dimethyl silicone oil and stirred continuously at 60-80℃ to load the silicone oil into its pores. Then the free silicone oil is removed to obtain silicone oil@TS-1 functional filler. S2. Preparation of polyurethane prepolymer: After dehydration of polyether polyol or polyester polyol, react with isocyanate to obtain polyurethane prepolymer with terminal -NCO groups. S3. Composite and Curing: Add the silicone oil@TS-1 functional filler and chain extender, accounting for 3-8 wt% of the total mass of the final coating, to the polyurethane prepolymer, mix evenly, remove air bubbles, and then pour for curing.

[0016] Furthermore, this includes the following steps: S1. Preparation of functional filler: The porous titanium silica molecular sieve TS-1 is immersed in dimethyl silicone oil and stirred continuously at 60-80℃ for 20-30 hours to load the silicone oil into its pores. Then, the free silicone oil is removed by vacuum filtration to obtain silicone oil@TS-1 functional filler. S2. Preparation of polyurethane prepolymer: After dehydrating polyether polyol or polyester polyol at 120°C and vacuum degree not lower than -0.095 MPa for 2-3 hours, react it with isocyanate at 75-85°C for 1.5-2.5 hours to obtain polyurethane prepolymer with terminal -NCO groups. S3. Composite and Curing: Add the silicone oil@TS-1 functional filler and chain extender, accounting for 3-8 wt% of the total mass of the final coating, to the polyurethane prepolymer. Mix evenly and remove air bubbles under a vacuum of not less than -0.095 MPa and a temperature of 70-80℃. Pour the mixture into a mold and cure it at 100-120℃ for 2-4 hours.

[0017] Furthermore, in step S3, the mixing is carried out under conditions of a vacuum degree not lower than -0.095 MPa and a temperature of 70-80°C.

[0018] Furthermore, in step S3, the mixing is carried out under a vacuum of not less than -0.095 MPa, a temperature of 70-80℃, a stirring speed of 400-600 rpm, and a mixing time of 25-35 minutes.

[0019] Furthermore, in step S2, the molar ratio of isocyanate to polyol is (0.8-1.2):1, calculated based on the -NCO group of isocyanate to the -OH group of polyol.

[0020] Furthermore, in step S3, the amount of chain extender added is (0.8-1.2):1, based on the molar ratio of the active hydrogen groups in its molecule to the -NCO groups in the polyurethane prepolymer.

[0021] Furthermore, in step S1, the mass ratio of the dimethyl silicone oil to the porous titanium silicate molecular sieve TS-1 is (5-15):1.

[0022] A third aspect of the present invention provides an application of the silicone oil slow-release antifouling coating as described above as an antifouling coating on the surface of ships, offshore platforms or marine pipelines.

[0023] Compared with the prior art, the beneficial effects of the present invention are as follows: 1. This invention provides a silicone oil slow-release antifouling coating. By selecting a porous titanium-silicon molecular sieve (TS-1) with both regular nanopores and titanium active centers as the core carrier, dimethyl silicone oil is fully adsorbed within its pores, resulting in a functional filler with a silicone oil loading of 30-50 wt%. Free silicone oil is transformed into a pore-bound state, effectively improving the problem of rapid release of silicone oil due to incompatibility. Subsequently, this functional filler is introduced into a polyurethane matrix at a specific ratio of 3-8 wt%, effectively ensuring sufficient filler amount to construct a continuous slow-release network and avoiding damage to the matrix continuity caused by excessive addition. The rigid TS-1 skeleton, as a nano-reinforcing phase, promotes interfacial bonding with polyurethane due to its surface properties, helping to overcome the disadvantage of ordinary inorganic fillers easily acting as stress defect points. The obtained coating not only achieves long-lasting antifouling function but also significantly increases the tensile strength from approximately 1.38 MPa in pure polyurethane to over 3.5 MPa, successfully solving the problem of achieving high strength and long lifespan synergistically in environmentally friendly antifouling coatings.

[0024] 2. The method for preparing the silicone oil slow-release antifouling coating provided by this invention involves selecting porous titanium silicate molecular sieve TS-1 as a dedicated carrier, and adsorbing and loading dimethyl silicone oil of a specific viscosity (50-100 cst) into its nanoscale pores at 60-80℃ to obtain silicone oil@TS-1 functional filler. Subsequently, this filler is introduced into a polyurethane system at a specific ratio of 3-8 wt%, and after vacuum mixing and thermosetting processes, a composite coating is finally formed. This achieves a synergistic unity of long-term, controllable slow release of the lubricant and a significant enhancement of the coating's mechanical properties, successfully transforming the rapid and disordered release of silicone oil caused by traditional physical blending into a slow and orderly replenishment, while simultaneously resulting in an unexpected and significant increase in the coating's tensile strength; it also exhibits excellent surface antifouling adhesion resistance and UV aging resistance. Attached Figure Description

[0025] Figure 1 Photographs of the antibacterial performance test results of different coatings: (a) blank control; (b) comparative example 1 (D1) pure polyurethane coating; (c) example 1 (E1) composite coating; (d) example 2 (E2) composite coating. Detailed Implementation

[0026] The present invention will now be described in further detail with reference to specific embodiments. However, this should not be construed as limiting the scope of the present invention to the following embodiments; all technologies implemented based on the content of the present invention fall within the scope of the present invention.

[0027] The present invention will be described in detail below with reference to embodiments and comparative examples. The purpose of this description is to more clearly illustrate the technical solutions and beneficial effects of the present invention, rather than to constitute any limitation on the scope of protection of the present invention.

[0028] I. Experimental Materials and General Testing Methods 1. Main raw materials and reagents Molecular sieve synthesis raw materials: tetraethyl orthosilicate (TEOS, analytical grade), tetrapropylammonium hydroxide (TPAOH, 25% aqueous solution, analytical grade), titanium trichloride (TiCl3, 15-20% hydrochloric acid solution, analytical grade), triethanolamine (TEOA, analytical grade), 30% hydrogen peroxide (H2O2, analytical grade), ammonium sulfate (analytical grade), and ammonium carbonate (analytical grade).

[0029] Seed crystal: Commercial TS-1 molecular sieve (Si / Ti ≈ 40) was used as a seed crystal for synthesis.

[0030] Lubricant: Dimethyl silicone oil with kinematic viscosities of 30 cst, 50 cst, 100 cst, and 200 cst (chemically pure).

[0031] Polyurethane raw materials: polytetrahydrofuran ether diol (PTMG, number average molecular weight Mn = 2000, industrial grade), which was vacuum dehydrated at 120℃ and -0.095 MPa for 2 hours before use; isophorone diisocyanate (IPDI, chemically pure); 1,4-butanediol (BDO, chemically pure).

[0032] Other: The water used in the experiment was deionized water.

[0033] 2. General Testing and Characterization Methods Mechanical property testing: According to national standard GB / T 1040.3-2006, the coated samples were cut into standard dumbbell-shaped specimens (gauge length 25 mm, width 4 mm). A universal testing machine was used, and tests were conducted at room temperature with a tensile rate of 50 mm / min. At least five parallel tests were performed on each group of samples, and the arithmetic mean of the results was taken, along with the standard deviation.

[0034] Silicone oil release behavior test: A precisely weighed (denoted as W0) regular coating sample (20 mm × 20 mm × 2 mm) is completely immersed in a sealed glass container containing 500 mL of artificial seawater (prepared according to ASTM D1141-52 standard). The container is placed in a constant temperature shaker and the release test is conducted at 25 ± 1℃ and 100 rpm. Samples are removed at predetermined time points (e.g., days 1, 3, 7, 14, and 30). The surface liquid is quickly blotted dry with filter paper, and then immediately placed in a 50℃ oven for 15 minutes to completely remove adsorbed water. After cooling to room temperature, the sample is weighed (denoted as W0). t The cumulative release rate of silicone oil (R) is calculated using the following formula: R (%) = [(W0 - W...] t ) / (W0× ω)] × 100%, where ω is the initial mass fraction of silicone oil in the coating.

[0035] Preliminary screening of antifouling performance (anti-algae adhesion): A common marine fouling algae, *Nitzschia closterium*, was selected for testing. Coated samples (25 mm × 25 mm) were immersed in an algae-containing solution with an algal density of approximately 1 × 10⁻⁶. 5 Algal cells were incubated in artificial seawater at a concentration of [number] cells / mL for 21 days in a light incubator (temperature: 20 ± 1℃; light cycle: 12 h light / 12 h dark). After incubation, the sample surface was gently rinsed three times with sterile seawater at a constant flow rate to remove loosely attached algal cells. Five fields of view were randomly selected and photographed under a stereomicroscope, and the average algal cell density per unit area was calculated using image analysis software.

[0036] UV aging resistance test: A UV aging test chamber equipped with a UVA-340 lamp was used. The test conditions were set as follows: irradiance 0.68 W / m² @ 340 nm, black panel temperature 60 ± 3℃, and continuous irradiation for 300 hours. After irradiation, the surface morphology changes of the samples (such as chalking, cracking, discoloration, etc.) were observed, and their tensile strength was tested. The strength retention rate was calculated as (strength after aging / initial strength × 100%).

[0037] II. Preparation of porous titanium-silicon molecular sieve (TS-1) TS-1 was synthesized using a hydrothermal crystallization method. 20.8 g of TEOS and 32.2 g of TPAOH solution were dissolved in 100 g of deionized water and reacted at 60 °C and 120 rpm for 6 hours to obtain a clear silica sol. In a separate container, 3.4 g of TiCl3 solution was diluted with 10 g of water, followed by the addition of 1.0 g of TEOA dissolved in 10 g of water and the solution to the diluted TiCl3 solution, followed by stirring for 15 minutes. Then, 1.0 g of 30% H2O2 diluted with 10 g of water was slowly added dropwise to the above mixture, and the solution gradually turned purple-red, yielding a stable titanium source solution. This titanium source solution was combined with the aforementioned silica sol, and 2.0 g of ammonium sulfate, 2.0 g of ammonium carbonate, and 0.05 g of TS-1 seed crystals were added, followed by continuous stirring for 2 hours to ensure homogeneity. The final mixture was transferred to a polytetrafluoroethylene-lined high-pressure reactor and statically crystallized at 170 °C for 72 hours. After the reaction was completed, the product was centrifuged, washed repeatedly with deionized water until neutral, dried in an oven at 100°C for 12 hours, and finally placed in a muffle furnace, heated to 550°C at 2°C / min and calcined for 6 hours to completely remove the template agent, yielding white TS-1 powder.

[0038] III. Preparation of Examples and Comparative Examples Comparative Example 1 (D1) Pure polyurethane reference coating Under dry nitrogen protection, 100.0 g of dehydrated PTMG (Mn=2000) was added to a four-necked flask equipped with a stirrer, thermometer, and condenser. The system temperature was lowered to 80°C, and 34.8 g of IPDI (controlling the molar ratio of NCO to OH at 1.05:1) was slowly added through a constant-pressure dropping funnel. The reaction was continued at 80°C for 2 hours, during which the -NCO group content was monitored periodically by di-n-butylamine titration until the theoretical value (approximately 6.5%) was reached, yielding a polyurethane prepolymer. Subsequently, the system temperature was adjusted to 75°C, and precisely measured BDO (molar ratio of -NCO groups in the prepolymer to 1:1) was added, followed by rapid stirring for 3 minutes to ensure homogeneity. The mixture was poured into a preheated (approximately 80°C) PTFE mold (size: 100 mm × 100 mm × 2 mm) and placed in a forced-air oven for curing at 110°C for 3 hours. After curing, the coating was demolded and aged for 7 days in a standard environment of 23±2℃ and 50±10% relative humidity to obtain a pure polyurethane coating sample, labeled as D1.

[0039] Comparative Example 2 (D2) Physical blend coating This comparative example is intended to simulate the common drawbacks of simply physically blending lubricants and fillers, as described in the background section. 3.0 g of TS-1 powder without any silicone oil loading (the same net content of TS-1 as in subsequent examples) and 2.4 g of dimethyl silicone oil with a viscosity of 50 cst (the same net content of silicone oil as in subsequent examples) were weighed and placed in a beaker. The mixture was manually stirred at room temperature for approximately 5 minutes to form a non-uniform paste mixture. 100 g of polyurethane prepolymer, prepared in the exact same manner as in D1, was taken and kept at 75°C. The above paste mixture was added to the prepolymer in one step. Subsequent mixing, degassing, BDO addition, casting, and curing process parameters were identical to those in D1. The resulting coating is labeled D2.

[0040] Example 1 (E1) Preparation of silicone oil@TS-1 functional filler: 5.0 g of the synthesized TS-1 powder was weighed and completely immersed in 50 g of dimethyl silicone oil with a viscosity of 50 cst. The mixture was placed in an oil bath at 70 °C and subjected to a loading reaction for 24 hours under continuous magnetic stirring. After the reaction, most of the free silicone oil was removed by gentle vacuum filtration using a Buchner funnel and quantitative filter paper. Subsequently, the resulting wet filter cake was transferred to a petri dish, spread evenly, and placed in a 70 °C forced-air oven for 2 hours to allow the residual silicone oil on the surface to further penetrate into the pores or volatilize, finally obtaining a silicone oil@TS-1 functional filler with a uniform appearance and no visible free oil. A small sample was taken for thermogravimetric analysis (TGA, nitrogen atmosphere, heating rate 10 °C / min to 800 °C), and the loading of silicone oil was calculated to be 45 wt% based on the weight loss curve.

[0041] Preparation of the composite coating: Accurately weigh 100 g of polyurethane prepolymer with the same formulation and process as in the preparation of D1, and maintain the temperature at 75℃. Accurately weigh 5.26 g of the functional filler prepared in step 1 (containing approximately 2.9 g of TS-1 and approximately 2.36 g of silicone oil) and add it to the prepolymer. This addition amount ensures that the functional filler has a theoretical mass percentage of 5.0 wt% in the final solid coating. Transfer the mixture to a vacuum mixer and mechanically stir at 500 rpm for 30 minutes under a vacuum of -0.095 MPa and at 75℃ to ensure uniform dispersion of the filler and thorough degassing. Then, add BDO in the same stoichiometric ratio as D1, stir rapidly, pour into a preheated mold, cure at 110℃ for 3 hours, and then age at room temperature for 7 days to obtain the composite coating sample, labeled E1.

[0042] Example 2 (E2) and Comparative Example 3 (D3) E2: Its preparation process is exactly the same as E1, the only difference being that in step 1, the viscosity of the dimethyl silicone oil used for impregnating TS-1 is changed to 100 cst. The final product is a functional filler with a silicone oil loading of approximately 42 wt%, and a coating is prepared according to the total proportion of E1 of 5.0 wt%, labeled as E2.

[0043] D3: Its preparation process is exactly the same as E1, the only difference being that in step 1, dimethyl silicone oil with a viscosity of 200 cst is used for impregnation, which exceeds the range protected by claim 1. The resulting coating is marked as D3.

[0044] Example 3 (E3) and Comparative Example 4 (D4) E3: Its preparation process is exactly the same as E1, the only difference being that in step 2, the amount of silicone oil@TS-1 functional filler added is adjusted to 2.94 g. This amount makes the total mass percentage of the functional filler in the final coating 2.9 wt%, which is considered the critical point of the 3 wt% lower limit in claim 1. The resulting coating is labeled E3.

[0045] D4: Its preparation process is exactly the same as E1, the only difference being that in step 2, the amount of silicone oil@TS-1 functional filler added is adjusted to 10.0 g. This amount results in the functional filler accounting for 9.1 wt% of the total mass in the final coating, exceeding the 8 wt% upper limit in claim 1. The resulting coating is labeled D4.

[0046] IV. Performance Test Results and Comparative Analysis Table 1. Basic mechanical properties of the coating and silicone oil release kinetics data Table 2: Comparison of antifouling performance and environmental aging resistance of coatings Test antibacterial properties: (1) Activation of bacterial strain: The refrigerated Escherichia coli slant strain was transferred to nutrient agar and cultured at 37°C for 24 hours. The transfer was repeated twice, and fresh bacteria were taken for subsequent antibacterial experiments.

[0047] (2) Sample preparation: Prepare polyurethane coating, composite coating of Example 1, composite coating of Example 2 and blank control ABS board that has only been polished in advance.

[0048] (3) Preparation of bacterial suspension: The activated bacteria were inoculated into the nutrient broth using a sterile inoculation loop and cultured in a constant temperature incubator at 37°C with shaking (150 rpm) for 24 h to ensure uniform bacterial dispersion. The bacterial count was determined using an appropriate method, and the bacterial suspension was diluted to 108 CFU / ml with PBS buffer as the inoculation solution (absorbance is approximately 0.1).

[0049] (4) Sample inoculation and culture: Take 0.1 ml of diluted bacterial suspension and drop it onto the sample surface. Perform 3 parallel experiments for each sample. Use sterile tweezers to cover the sample plate with a pre-sterilized polyethylene film in a clean bench. During this process, make sure that the bacterial suspension is evenly spread on the sample plate surface. Then place the sample plate in a petri dish with a moistened filter paper at the bottom (maintain humidity greater than 90%), cover the petri dish and place it in a 37℃ constant temperature incubator for continuous static culture for 24 hours. (5) Bacterial recovery from the sample surface: Take out the cultured sample, rinse the sample plate and film repeatedly with 10 ml of elution solution, shake well, and then dilute it 10, 100 and 1000 times respectively using the tenfold dilution method. Take 0.1 mL of the diluted inoculum solution and inoculate it into nutrient agar using the plate spreading method. Put it back into the constant temperature incubator for 24 h.

[0050] (6) Take out the petri dish, take a picture, count the number of colonies on the surface, and finally calculate the antibacterial rate according to Proof 1.

[0051] Formula 1 The colony count in the final test of the blank control group is recorded as N0, and the colony count in the control group containing the test sample is recorded as Ni. The antibacterial rate is R. The above test must be repeated at least twice to ensure the accuracy of the results. According to the formula, the larger the R value, the stronger the antibacterial activity of the sample, and vice versa. Figure 1 As shown in the figure, the prepared composite coating has obvious antibacterial properties, with an antibacterial rate of up to 99%.

[0052] This invention provides a silicone oil slow-release antifouling coating. By selecting a porous titanium-silicon molecular sieve (TS-1) with both regular nanopores and titanium active centers as the core carrier, dimethyl silicone oil is fully adsorbed within its pores, resulting in a functional filler with a silicone oil loading of 30-50 wt%. Free silicone oil is transformed into a pore-bound state, effectively improving the problem of rapid release of silicone oil due to incompatibility. Subsequently, this functional filler is introduced into a polyurethane matrix at a specific ratio of 3-8 wt%, effectively ensuring sufficient filler amount to construct a continuous slow-release network and avoiding damage to the matrix continuity caused by excessive addition. The rigid TS-1 skeleton, as a nano-reinforcing phase, promotes interfacial bonding with polyurethane due to its surface properties, helping to overcome the disadvantage of ordinary inorganic fillers easily acting as stress defect points. The obtained coating not only achieves long-lasting antifouling function but also significantly increases the tensile strength from approximately 1.38 MPa in pure polyurethane to over 3.5 MPa, successfully solving the problem of achieving a synergistic effect of high strength and long lifespan in environmentally friendly antifouling coatings.

[0053] In some embodiments, porous titanium-silicon molecular sieve TS-1 can be synthesized by hydrothermal method, or a commercially available TS-1 product that meets the silicon-to-titanium ratio (Si / Ti=30-50) requirement of the present invention can be used.

[0054] In some embodiments, the polyurethane matrix of the present invention may be any type of polyurethane commonly used in the art, including but not limited to polyurethanes obtained by reacting polyether polyols, polyester polyols, etc., with diisocyanates (such as toluene diisocyanate TDI, diphenylmethane diisocyanate MDI, isophorone diisocyanate IPDI, etc.). Preferably, a polyether-type polyurethane with good flexibility and excellent hydrolysis resistance is used, such as the polytetrahydrofuran ether diol (PTMG) and IPDI system used in this embodiment.

[0055] In some embodiments, the silicone oil loading in the silicone oil@TS-1 functional filler is 30-50 wt%.

[0056] In some embodiments, the viscosity of the dimethyl silicone oil is 50-100 cst.

[0057] In some embodiments, the molar ratio (Si / Ti) of silicon to titanium in the porous titanium-silicon molecular sieve TS-1 is 30-50.

[0058] A second aspect of the present invention provides a method for preparing the above-mentioned silicone oil slow-release antifouling coating, comprising the following steps: S1. Preparation of functional filler: The porous titanium silica molecular sieve TS-1 is immersed in dimethyl silicone oil and stirred continuously at 60-80℃ to load the silicone oil into its pores. Then the free silicone oil is removed to obtain silicone oil@TS-1 functional filler. S2. Preparation of polyurethane prepolymer: After dehydration of polyether polyol or polyester polyol, react with isocyanate to obtain polyurethane prepolymer with terminal -NCO groups. S3. Composite and Curing: Add the silicone oil@TS-1 functional filler and chain extender, accounting for 3-8 wt% of the total mass of the final coating, to the polyurethane prepolymer, mix evenly, remove air bubbles, and then pour for curing.

[0059] In some embodiments, the following steps are included: S1. Preparation of functional filler: The porous titanium silica molecular sieve TS-1 is immersed in dimethyl silicone oil and stirred continuously at 60-80℃ for 20-30 hours to load the silicone oil into its pores. Then, the free silicone oil is removed by vacuum filtration to obtain silicone oil@TS-1 functional filler. S2. Preparation of polyurethane prepolymer: After dehydrating polyether polyol or polyester polyol at 120°C and vacuum degree not lower than -0.095 MPa for 2-3 hours, react it with isocyanate at 75-85°C for 1.5-2.5 hours to obtain polyurethane prepolymer with terminal -NCO groups. S3. Composite and Curing: Add the silicone oil@TS-1 functional filler and chain extender, accounting for 3-8 wt% of the total mass of the final coating, to the polyurethane prepolymer. Mix evenly and remove air bubbles under a vacuum of not less than -0.095 MPa and a temperature of 70-80℃. Pour the mixture into a mold and cure it at 100-120℃ for 2-4 hours.

[0060] In some embodiments, in step S3, the mixing is carried out under conditions of a vacuum degree not lower than -0.095 MPa and a temperature of 70-80°C.

[0061] In some embodiments, in step S3, the mixing is carried out under a vacuum of not less than -0.095 MPa, a temperature of 70-80°C, a stirring speed of 400-600 rpm, and a mixing time of 25-35 minutes.

[0062] In some embodiments, in step S2, the molar ratio of isocyanate to polyol is (0.8-1.2):1, calculated based on the -NCO group of isocyanate to the -OH group of polyol.

[0063] In some embodiments, in step S3, the amount of chain extender added is (0.8-1.2):1, based on the molar ratio of active hydrogen groups in its molecule to -NCO groups in the polyurethane prepolymer.

[0064] In some embodiments, in step S1, the mass ratio of the dimethyl silicone oil to the porous titanium silicate molecular sieve TS-1 is (5-15):1.

[0065] This embodiment also provides an application of the silicone oil slow-release antifouling coating as described above as an antifouling coating on the surface of ships, offshore platforms or marine pipelines.

[0066] The above description is only a preferred embodiment of the present invention and is not intended to limit the present invention. Any modifications, equivalent substitutions, and improvements made within the spirit and principles of the present invention should be included within the protection scope of the present invention.

Claims

1. A silicone oil slow-release antifouling coating, which is a polyurethane composite coating, characterized in that, The product contains a functional filler dispersed in a polyurethane matrix, wherein the functional filler is silicone oil@TS-1 formed by loading dimethyl silicone oil into the channels of a porous titanium silica molecular sieve TS-1; The functional filler accounts for 3-8 wt% of the coating by mass.

2. The silicone oil slow-release antifouling coating according to claim 1, characterized in that, In the silicone oil@TS-1 functional filler, the loading of silicone oil is 30-50 wt%.

3. The silicone oil slow-release antifouling coating according to claim 1 or 2, characterized in that, The viscosity of the dimethyl silicone oil is 50-100 cst.

4. The silicone oil slow-release antifouling coating according to claim 1, characterized in that, The porous titanium-silicon molecular sieve TS-1 has a silicon to titanium molar ratio (Si / Ti) of 30-50.

5. A method for preparing a silicone oil slow-release antifouling coating as described in any one of claims 1-4, characterized in that, Includes the following steps: S1. Preparation of functional filler: The porous titanium silica molecular sieve TS-1 is immersed in dimethyl silicone oil and stirred continuously at 60-80℃ to load the silicone oil into its pores. Then the free silicone oil is removed to obtain silicone oil@TS-1 functional filler. S2. Preparation of polyurethane prepolymer: After dehydration of polyether polyol or polyester polyol, react with isocyanate to obtain polyurethane prepolymer with terminal -NCO groups. S3. Composite and Curing: Add the silicone oil@TS-1 functional filler and chain extender, accounting for 3-8 wt% of the total mass of the final coating, to the polyurethane prepolymer, mix evenly, remove air bubbles, and then pour for curing.

6. The method according to claim 5, characterized in that, In step S3, the mixing is carried out under conditions of a vacuum degree not lower than -0.095 MPa and a temperature of 70-80℃.

7. The application of the silicone oil slow-release antifouling coating according to any one of claims 1-4 as an antifouling coating on the surface of ships, offshore platforms or marine pipelines.

Images