Preparation method of composite material for synergistically preventing barnacles from being attached to hull

Abstract

The invention relates to the technical field of ocean engineering antifouling materials, and particularly discloses a preparation method of a composite material for synergistically preventing barnacles from being attached to a hull. The method comprises the following steps: preparing a woven fabric with high density and smooth surface as a physical barrier layer, compounding a chitosan-modified drug-loaded microcapsule with biodegradable polyester to prepare a skin-core structure fiber layer with a slow release function, and finally compounding the two layers through a hot rolling microdot bonding process. According to the invention, a multi-stage protection system with a synergistic effect of a physical barrier and chemical slow release is constructed, controllable and long-acting release of the antifouling agent is realized, and the problems of sudden release of the antifouling agent and easy shedding of a coating in the prior art are effectively solved. The composite material has the advantages of being environmentally friendly, long in protection period, firm in combination and the like, and is suitable for barnacle attachment protection of ships and ocean facilities.

Description

Technical Field

[0001] This invention relates to the field of marine engineering antifouling materials technology, specifically a method for preparing a composite material for synergistic protection against barnacle attachment to ship hulls. Background Technology

[0002] Marine biofouling, particularly the attachment of hard fouling organisms such as barnacles, is a long-standing global problem that plagues marine engineering facilities. When barnacle larvae seek suitable attachment sites, they secrete a highly adhesive substance that allows them to firmly adhere and rapidly calcify, leading to a series of serious consequences, including significantly increased ship drag, accelerated corrosion of marine facilities, clogging of aquaculture cages, and interference with underwater sensor signals.

[0003] To address this challenge, existing technologies are mainly developing in the following directions: First, traditional chemical antifouling paints, which inhibit biofouling by releasing toxic biocides (such as organotin and cuprous oxide), but have the problems of high environmental toxicity, easy ecological accumulation, and are subject to strict international environmental regulations; Second, low surface energy antifouling coatings, which rely on extremely low interfacial energy to make it difficult for fouling organisms to attach or easy to detach, but their effectiveness is limited under static or low-speed conditions, and the coating has poor mechanical strength and is easily worn; Third, biomimetic microstructure surfaces, which interfere with larval attachment by constructing micro-nano topological structures, but the preparation process is complex and costly, and they are prone to failure due to wear or algal cover in harsh marine environments; Fourth, textile-based physical protective layers, which use high-performance synthetic fiber fabrics as physical barriers, provide new ideas, but still generally rely on surface-coated antifouling coatings, failing to fundamentally solve the problems of easy coating detachment and uncontrollable release of antifouling agents.

[0004] However, all of the above technologies share a fundamental common flaw: they rely on only a single or limited protective mechanism and fail to construct a multi-layered and synergistic protective system that matches the multi-stage attachment process of barnacles, namely, "larval dispersal - surface contact - adhesive adhesion - calcification growth".

[0005] Specifically, chemical antifouling methods neglect physical barriers and the release mode is mostly uncontrollable "burst release"; physical antifouling methods lack long-term and intelligent chemical inhibition methods; and even existing core-shell composite fiber technologies that combine fiber structure and chemical function generally have problems such as easy delamination of the core-shell layer, uneven microcapsule dispersion, single controlled release mechanism, and unstable release, resulting in short-lived antifouling effect, insufficient structural reliability, and difficulty in adapting to complex and ever-changing marine engineering scenarios.

[0006] Therefore, how to construct a multi-layered, synergistic anti-fouling system to achieve long-term, controllable anti-fouling while taking into account environmental friendliness and engineering applicability has become a key technical bottleneck that urgently needs to be overcome in this field. Summary of the Invention

[0007] The purpose of this invention is to overcome the shortcomings of the prior art and provide a method for preparing a composite material for synergistic protection against barnacle adhesion to ship hulls, solving the technical problems of "traditional coatings being prone to peeling off and the sudden release effect of antifouling components leading to the inability to achieve long-term antifouling".

[0008] To achieve the above objectives, the present invention is implemented using the following technical solution: In a first aspect, the present invention provides a method for preparing a composite material for synergistic protection against barnacle attachment to a ship's hull, comprising the following steps: (1) Aramid and polyethylene terephthalate are made into blended yarns, which are woven into high-density woven fabrics. The woven fabrics are desized, scouring, cleaned and dried, and then subjected to high-temperature and high-pressure calendering to obtain a surface modified layer. (2) Modified microcapsules carrying antifouling agents are blended with biodegradable polyester as the skin layer material, and the above-mentioned blended yarn is used as the core layer material. Skin-core composite fibers are prepared by skin-core composite spinning, and the fibers are woven into fabric to form a slow-release antifouling layer. (3) The slow-release antifouling layer fabric obtained in step (2) is laminated with the surface modified layer obtained in step (1), and the two layers are bonded at the contact point by hot rolling micro-dot bonding process to obtain a protective barnacle attachment hull composite material.

[0009] Specifically, the high-temperature and high-pressure calendering process in step (1) uses a three-roll calender with an upper roll temperature of 120~140℃ and a pressure of 20~30 kg / cm². 2 The processing speed is 10~20m / min.

[0010] Specifically, the weight ratio of the modified microcapsules to the biodegradable polyester in step (2) is 1:(18-21).

[0011] Specifically, the core-sheath composite spinning process in step (2) adopts zoned temperature control, wherein: the processing and conveying temperature of the sheath material is 100~140℃, the final temperature of the core-sheath composite spinning assembly is 180~220℃, and the residence time in the high temperature zone of 180~220℃ is 0.5~3s.

[0012] Specifically, the modified microcapsules in step (2) are prepared by first preparing pre-modified microcapsules with antifouling agent and polylactic acid-hydroxyacetic acid copolymer, and then modifying the surface of the pre-modified microcapsules with chitosan solution.

[0013] Specifically, the pre-modified microcapsules have a particle size of 0.1~3 μm and a capsule wall thickness of 1~3 μm. After being modified with chitosan, the modified microcapsules have a particle size of 0.12~3.1 μm and a chitosan coating layer thickness of 10~50 nm.

[0014] Specifically, the antifouling agent is one of 1,4,2-oxathiazine-4-oxide and natural alum.

[0015] Specifically, in step (1), the warp density of the high-density woven fabric is 42 threads / cm, the weft density is 40 threads / cm, and the yarn gap is controlled at 0.07~0.09mm.

[0016] Specifically, in step (2), the diameter of the composite fiber is 30 μm and the thickness of the sheath of the composite fiber is 6~9 μm.

[0017] Specifically, the hot rolling micro-dot bonding process parameters in step (3) are: the roll temperature of the hot rolling mill is 170~190℃, the pressure is 0.25~0.35MPa, and the contact time is 1~2s.

[0018] Compared with the prior art, the beneficial effects achieved by the present invention are: (1) This invention designs a high-density woven fabric with specific yarn gaps as a physical barrier, and combines it with high temperature and high pressure calendering to give it a low roughness and high hydrophobicity surface, thus constructing the first line of defense to effectively block barnacle larvae from contacting and attaching, and achieving synergistic protection of physical barrier and surface smoothing.

[0019] (2) The present invention uses microcapsule encapsulation and chitosan surface modification technology to encapsulate the antifouling agent in the polylactic acid-glycolic acid copolymer capsule wall, and then improves the dispersion and binding of microcapsules in polycaprolactone matrix through chitosan hydrophilic modification; at the same time, through the zoned temperature control and short-time heat exposure process of core-sheath composite spinning, the microcapsule structure is completely protected while ensuring the fiber forming quality, and the stable, controllable and long-term release of antifouling agent is achieved.

[0020] (3) The present invention uses hot rolling micro-dot bonding process to composite the surface modified layer and the slow-release antifouling layer. Local micro-welding points are formed only at the fiber intersections. While ensuring strong interlayer bonding and durable structure, the breathability and flexibility of the fabric are maintained to the greatest extent. This avoids the performance degradation caused by full-surface coating. The process is simple and efficient and suitable for large-scale production. Detailed Implementation

[0021] The technical solutions of the present invention will be clearly and completely described below with reference to the embodiments of the present invention. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those of ordinary skill in the art without creative effort are within the scope of protection of the present invention.

[0022] The preparation method of the synergistic protective barnacle attachment hull composite material described in this invention is based on the three-level synergistic protection concept of "physical barrier - surface modification - chemical slow release". It constructs a multi-level, long-lasting, and environmentally friendly anti-barnacle attachment system. This system first forms a macroscopic physical barrier through high-density woven fabric, effectively blocking the contact and invasion of barnacle larvae. Secondly, the surface is made smooth through high-temperature and high-pressure calendering, reducing the adhesion strength of larvae in the early stage of attachment. Finally, the antifouling agent microcapsules embedded in the core-sheath composite fiber realize the stable, controllable, and long-lasting release of the antifouling components, thereby implementing multi-stage synergistic intervention in the entire process of barnacle "larval diffusion - surface contact - adhesive adhesion - calcification growth".

[0023] This technical solution fundamentally addresses the challenges of long-term protection caused by the easy detachment of traditional antifouling coatings and the initial burst release of antifouling agents. The solution achieves this by: uniformly dispersing drug-loaded microcapsules within a biodegradable outer layer using a core-sheath composite fiber structure; and utilizing a dual mechanism of slow degradation of the outer layer material and diffusion control through the microcapsule wall to achieve programmed release of the antifouling agent. Simultaneously, a robust micro-welded structure is formed between the surface-modified layer and the slow-release antifouling layer through a hot-rolled micro-dot bonding process, ensuring interlayer bonding strength and overall reliability, and avoiding the risk of coating peeling. This system not only significantly extends the antifouling period but also considers marine environmental friendliness and engineering applicability, providing an innovative solution for long-term biofouling protection of ships and marine facilities.

[0024] A method for preparing a composite material for synergistic protection against barnacle attachment to a ship's hull includes the following steps: (1) Aramid and polyethylene terephthalate are blended at a weight ratio of (0.67~1.5):1 to produce a 20-count blended yarn. This yarn is used as warp and weft yarns and woven into a high-density woven fabric using an air-jet loom. The high-density woven fabric is then desized with α-amylase, scourted with dilute caustic soda, washed with water, and dried. Finally, it is subjected to high-temperature and high-pressure treatment using a three-roll calender. The upper roll temperature is 120~140℃ and the pressure is 20~30kg / cm. 2 The surface-modified layer was obtained by moving the material at a speed of 10~20m / min.

[0025] (2) Polylactic acid-glycolic acid copolymer, 1,4,2-oxathiazine-4-oxide and dichloromethane were mixed at a mass ratio of 1:(0.1~0.15):(20~30) as the oil phase, and the aqueous phase was an aqueous solution containing 1~3% (w / v) polyvinyl alcohol. The oil phase and the aqueous phase were mixed at a volume ratio of 1:(6~10) and emulsified at a high speed of 10000~14000 r / min at 25~30℃. Then the solvent was evaporated, washed with deionized water and dried to obtain pre-modified microcapsules. Chitosan, glacial acetic acid and deionized water were mixed at a mass ratio of 1:(0.8~1.2):(100~110) to prepare a mixed solution. The pre-modified microcapsules and the mixed solution were mixed at a weight ratio of 1:(20~30) and stirred at 40~50℃ for 1~2 h. The pH was adjusted to neutral with 0.1mol / L NaOH and collected by centrifugation to obtain modified microcapsules. (3) The modified microcapsules and polycaprolactone particles were fed into a twin-screw extruder at a weight ratio of 1:(18~21) and melted at 100~140℃ to obtain blended particles. The blended particles were used as the skin material and the blended yarn from step (1) was used as the core material. The yarn was spun through a skin-core composite spinning device. The process adopted zoned temperature control: the processing and conveying temperature of the skin material was 100~140℃, the final temperature of the skin-core composite spinning assembly was 180~220℃, and the draw ratio was 2.5~3.5 times. Composite fibers with a diameter of 30um were prepared and the composite fibers were woven into fabric to form a slow-release antifouling layer.

[0026] (4) The above-mentioned slow-release antifouling layer fabric is laminated with the surface modified layer obtained in step (2), and the hot rolling micro-dot bonding process is used for treatment. The temperature of the hot rolling mill rolls is 170~190℃, the pressure is 0.25~0.35MPa, the contact time is 1~2s, and it is cut into a composite material suitable for the bottom of the ship.

[0027] In this invention, the warp density of the high-density woven fabric is 42 threads / cm and the weft density is 40 threads / cm, with the yarn gap controlled at 0.07~0.09mm. In this invention, the gap size is much smaller than the body size of barnacle gland larvae, which can effectively prevent the larvae from directly penetrating the inside of the fabric, thereby forming a physical barrier.

[0028] In this invention, the polylactic acid-glycolic acid copolymer has a lactic acid / glycolic acid molar ratio of 3~5.7:1, a viscosity-average molecular weight of 30000~50000 Da, and carboxyl groups as the main end groups. Its residual monomer content is less than 0.5%. When the pre-modified microcapsules are prepared by the O / W emulsification-solvent evaporation method, the particle size of the pre-modified microcapsules is 0.1~3 μm, the polylactic acid-glycolic acid copolymer capsule wall thickness is 1~3 μm, and after chitosan surface modification, the modified microcapsules have a particle size of 0.12~3.1 μm and a chitosan coating layer thickness of 10~50 nm.

[0029] In this invention, the polycaprolactone has a number-average molecular weight of 30,000 to 80,000. The composite fiber prepared in step (3) has a sheath thickness of 6 to 9 μm, which accounts for about 20% to 30% of the total diameter of the monofilament (30 μm). The sheath-core structure forms a strong physical entanglement and anchoring at the interface through high-temperature melting and stretching during the spinning process, ensuring that there is no sheath peeling during long-term use in the marine environment.

[0030] In this invention, the core of the core-sheath composite spinning equipment for zoned temperature control in spinning settings lies in exposing the sheath material containing heat-sensitive microcapsules to an environment of 180-220°C for only a very short time (0.5-3s) through the high-temperature spinning components, followed by rapid cooling and solidification. Due to the extremely short high-temperature exposure time, the heat transfer history to the microcapsules inside the sheath is limited, insufficient to destroy the integrity of its chitosan-modified layer and polylactic acid-glycolic acid copolymer capsule wall. Thus, while ensuring high-quality fiber formation, the complete embedding of functional microcapsules is achieved. This process design ensures the successful construction of antifouling agent encapsulation and sustained-release functions.

[0031] In this invention, the hot-rolled micro-dot bonding process not only bonds the surface-modified layer and the slow-release antifouling layer at the contact point, but more importantly, the heat causes the polycaprolactone skin at the intersection of the slow-release antifouling layer fabric to undergo local selective melting. The molten polycaprolactone penetrates upward and bonds the fibers of the surface-modified layer, and strengthens its own fabric nodes downward, thereby forming a large number of uniformly distributed micro-welding points between the two layers of fabric. This structure not only gives the composite material excellent interlayer bonding force, but also avoids the loss of breathability and decrease in flexibility caused by full-surface coating.

[0032] Example 1; (1) Aramid and polyethylene terephthalate were blended at a weight ratio of 0.67:1 to produce a 20-count blended yarn. This yarn was used as warp and weft yarns and woven into a high-density woven fabric using an air-jet loom. The high-density woven fabric was desized by α-amylase, scouring with dilute caustic soda, washing with water, and drying. Then, it was subjected to high-temperature and high-pressure treatment using a three-roll calender with an upper roll temperature of 120°C and a pressure of 20 kg / cm. 2 The surface-modified layer was obtained by moving the material at a speed of 10 m / min.

[0033] (2) Polylactic acid-glycolic acid copolymer, 1,4,2-oxathiazine-4-oxide and dichloromethane were mixed at a mass ratio of 1:0.1:20 as the oil phase and the aqueous phase was an aqueous solution containing 1% (w / v) polyvinyl alcohol. The oil phase and the aqueous phase were mixed at a volume ratio of 1:6 and emulsified at 25°C and 10000 r / min. The solvent was then evaporated, washed with deionized water and dried to obtain pre-modified microcapsules. Chitosan, glacial acetic acid and deionized water were mixed at a mass ratio of 1:0.8:100 to prepare a mixed solution. The pre-modified microcapsules and the mixed solution were mixed at a weight ratio of 1:20 and stirred at 40°C for 1 h. The pH was adjusted to neutral with 0.1 mol / L NaOH and the modified microcapsules were collected by centrifugation. (3) The above-mentioned hydrophilic microcapsules and polycaprolactone particles are fed into a twin-screw extruder at a weight ratio of 1:18 and melted at 100°C to obtain blended particles. The blended particles are used as the skin material and the blended yarn in step (1) is used as the core material. The process adopts zoned temperature control: the processing and conveying temperature of the skin material is 100°C, the final temperature of the skin-core composite spinning assembly is 180°C, the draw ratio is 2.5 times, and a composite fiber with a diameter of 30 μm is prepared. The composite fiber is woven into a fabric to form a slow-release antifouling layer.

[0034] (4) The above-mentioned slow-release antifouling layer fabric is laminated with the surface modified layer obtained in step (2), and the hot rolling micro-dot bonding process is used for treatment. The temperature of the hot rolling mill roll is 170°C, the pressure is 0.25MPa, the contact time is 1s, and it is cut into a composite material suitable for the bottom of the ship.

[0035] Example 2; (1) Aramid and polyethylene terephthalate were blended at a weight ratio of 1.1:1 to produce a 20-count blended yarn. This yarn was used as warp and weft yarns and woven into a high-density woven fabric using an air-jet loom. The high-density woven fabric was desized by α-amylase, scouring with dilute caustic soda, washed with water, and dried. Then, it was subjected to high-temperature and high-pressure treatment using a three-roll calender with an upper roll temperature of 130°C and a pressure of 25 kg / cm. 2 The surface-modified layer was obtained by moving the material at a speed of 15 m / min.

[0036] (2) Polylactic acid-glycolic acid copolymer, 1,4,2-oxathiazine-4-oxide and dichloromethane were mixed at a mass ratio of 1:0.12:25 as the oil phase and the aqueous phase was an aqueous solution containing 2% (w / v) polyvinyl alcohol. The oil phase and the aqueous phase were mixed at a volume ratio of 1:8 and emulsified at 28°C and 12000 r / min. The solvent was then evaporated, washed with deionized water and dried to obtain pre-modified microcapsules. Chitosan, glacial acetic acid and deionized water were mixed at a mass ratio of 1:1.1:105 to prepare a mixed solution. The pre-modified microcapsules and the mixed solution were mixed at a weight ratio of 1:25 and stirred at 45°C for 1.5 h. The pH was adjusted to neutral with 0.1 mol / L NaOH and the modified microcapsules were collected by centrifugation. (3) The modified microcapsules and polycaprolactone particles were fed into a twin-screw extruder at a weight ratio of 1:20 and melted at 120°C to obtain blended particles. The blended particles were used as the skin material and the blended yarn in step (1) was used as the core material. The process adopted zoned temperature control: the processing and conveying temperature of the skin material was 120°C, the final temperature of the skin-core composite spinning assembly was 200°C, the draw ratio was 3 times, and a composite fiber with a diameter of 30 μm was prepared. The composite fiber was woven into a fabric to form a slow-release antifouling layer.

[0037] (4) The above-mentioned slow-release antifouling layer fabric is laminated with the surface modified layer obtained in step (2), and the hot rolling micro-dot bonding process is used for treatment. The temperature of the hot rolling mill roll is 180°C, the pressure is 0.3MPa, the contact time is 1s, and it is cut into a composite material suitable for the bottom of the ship.

[0038] Example 3; (1) Aramid and polyethylene terephthalate were blended at a weight ratio of 1.5:1 to produce a 20-count blended yarn. This yarn was used as warp and weft yarns and woven into a high-density woven fabric using an air-jet loom. The high-density woven fabric was desized by α-amylase, scouring with dilute caustic soda, washing with water, and drying. Then, it was subjected to high-temperature and high-pressure treatment using a three-roll calender with an upper roll temperature of 140°C and a pressure of 30 kg / cm. 2 The surface-modified layer was obtained by moving the material at a speed of 20 m / min.

[0039] (2) Polylactic acid-glycolic acid copolymer, 1,4,2-oxathiazine-4-oxide and dichloromethane were mixed at a mass ratio of 1:0.15:25 as the oil phase and the aqueous phase was an aqueous solution containing 3% (w / v) polyvinyl alcohol. The oil phase and the aqueous phase were mixed at a volume ratio of 1:10 and emulsified at 30°C and 14000 r / min. The solvent was then evaporated, washed with deionized water and dried to obtain pre-modified microcapsules. Chitosan, glacial acetic acid and deionized water were mixed at a mass ratio of 1:1.2:110 to prepare a mixed solution. The pre-modified microcapsules and the mixed solution were mixed at a weight ratio of 1:30 and stirred at 50°C for 2 h. The pH was adjusted to neutral with 0.1 mol / L NaOH and the modified microcapsules were collected by centrifugation. (3) The modified microcapsules and polycaprolactone particles were fed into a twin-screw extruder at a weight ratio of 1:21 and melted at 140°C to obtain blended particles. The blended particles were used as the skin material and the blended yarn in step (1) was used as the core material. The process adopted zoned temperature control: the processing and conveying temperature of the skin material was 140°C, the final temperature of the skin-core composite spinning assembly was 220°C, the draw ratio was 3.5 times, and a composite fiber with a diameter of 30 μm was prepared. The composite fiber was woven into a fabric to form a slow-release antifouling layer.

[0040] (4) The above-mentioned slow-release antifouling layer is laminated with the surface modified layer obtained in step (2), and the hot rolling micro-dot bonding process is used for treatment. The temperature of the hot rolling mill roll is 190°C, the pressure is 0.35MPa, the contact time is 2s, and it is cut into a composite material suitable for the bottom of the ship.

[0041] Comparative Example 1; The difference between Comparative Example 1 and Example 2 lies in the difference in steps (2) and (3). The process of preparing microcapsules in step (2) is modified as follows: Weigh 1,4,2-oxathiazine-4-oxide powder with a total mass equal to that of the antifouling agent in Example 2. At the same time, step (3) is modified as follows: Dry premix the above 1,4,2-oxathiazine-4-oxide powder with polycaprolactone (PCL) particles at a weight ratio (antifouling agent:PCL) of 1:100, and then add double... The screw extruder melts and blends at 120°C to obtain blended particles. Subsequently, the blended particles are used as the skin material, and the blended yarn from step (1) is used as the core material. The process is carried out through a skin-core composite spinning device. The process adopts zoned temperature control: the processing and conveying temperature of the skin material is 120°C, the final temperature of the skin-core composite spinning assembly is 200°C, the draw ratio is 4 times, and a composite fiber with a diameter of 30 μm is prepared. The composite fiber is woven into a fabric to form a slow-release anti-fouling layer. The remaining steps are the same as in Example 2.

[0042] Comparative Example 2; The difference between Comparative Example 2 and Example 2 lies in the difference in step (1). Step (1) is modified as follows: Aramid and polyethylene terephthalate are blended at a weight ratio of 1.5:1 to make a 20-count blended yarn. The yarn is used as warp and weft yarns and woven into a high-density woven fabric using an air-jet loom. The high-density woven fabric is desized by α-amylase, scourted with dilute caustic soda, washed with water, and dried to obtain a surface modified layer. The remaining steps are the same as in Example 2.

[0043] Comparative Example 3; The difference between Comparative Example 3 and Example 2 lies in step (2). Step (2) is modified as follows: Polylactic acid-glycolic acid copolymer, 1,4,2-oxathiazine-4-oxide and dichloromethane are mixed at a mass ratio of 1:0.12:25 as the oil phase, and the aqueous phase is an aqueous solution containing 2% (w / v) polyvinyl alcohol. The oil phase and the aqueous phase are mixed at a volume ratio of 1:8 and emulsified at a high speed of 12000 r / min. Then the solvent is evaporated, washed with deionized water, and dried to obtain modified microcapsules; the remaining steps are the same as in Example 2.

[0044] Test method: Surface roughness test: According to the standard method of GB / T10610-2009, the arithmetic mean deviation (Ra value) of the profile of the fabric surface after calendering is measured using a non-contact surface profilometer to detect the smoothing effect of the surface modification layer.

[0045] Hydrophobicity test: The static water contact angle of the material surface was measured using a contact angle meter at 25°C and 50% relative humidity.

[0046] Mechanical property testing: According to GB / T3923.1 standard, a universal testing machine is used to stretch the specimen to fracture at a specified speed, record the maximum load, and calculate the fracture strength; the material is subjected to a 400-hour xenon lamp accelerated aging test. After aging, the fracture strength is retested according to the above fracture strength test method. The strength retention rate is calculated based on the percentage of the fracture strength after aging to the initial fracture strength.

[0047] Intelligent sustained-release function test: Precisely weighed composite material samples were immersed in standard artificial seawater and subjected to simulated immersion at a constant temperature (25±3℃). High-performance liquid chromatography (HPLC) was used to periodically determine the cumulative release percentage of the antifouling agent in the immersion solution. To intuitively characterize the core advantage of the "sustainable-release antifouling layer" in overcoming burst release and achieving stable and long-lasting release, the following two key indicators were used for evaluation: Burst Release Index: This is the percentage of the cumulative release of the antifouling agent in the first 7 days of immersion relative to its total release over 180 days. The lower the value, the weaker the initial burst release effect and the more stable the release initiation.

[0048] Release half-life: refers to the time required for the cumulative release of the antifouling agent to reach 50% of its total release over 180 days. The larger the value, the slower the release rate and the better the long-lasting effect.

[0049] Seaborne barnacle adhesion rate test: According to GB / T5370-2007 standard, each sample was placed in a typical barnacle-contaminated sea area for a 180-day seaborne immersion test. After the test, the adhesion rate was calculated by image analysis to determine the percentage of barnacle coverage area per unit area of ​​the sample. The results are shown in Table 1.

[0050] Table 1

[0051] After high temperature and high pressure calendering, the surfaces of Examples 1-3 simultaneously possess high contact angles and low surface roughness. This indicates that the material surface has been successfully constructed into a dense, smooth, and hydrophobic physical interface, making it difficult for barnacle larvae to wet and spread their mucus.

[0052] Comparative Example 1 shows that, with the same total amount of antifouling agent as in Example 2, due to the lack of microcapsule encapsulation and controlled release barrier, the antifouling agent undergoes a violent burst release in the early stage of immersion (burst release index as high as 68.5%), and most of it is released in a very short time (half-life of only 22 days). This causes the antifouling agent in the material to be exhausted in a short period of time, and it cannot provide long-term protection. After 180 days, the actual sea adhesion rate is as high as about 25.31%, indicating that the microcapsule system achieves intelligent, stable and long-term controlled release of the antifouling agent.

[0053] Comparative Example 2 shows that because the surface roughness provides a strong adhesion base for barnacles, its antifouling effectiveness against barnacles is significantly lower than that of the embodiments.

[0054] Comparative Example 3 illustrates that the microcapsules, without chitosan hydrophilic modification, exhibit poor dispersibility and interfacial binding in the PCL matrix. The microcapsules are prone to aggregation, resulting in partial failure of the controlled-release function. The problem of "initial burst release followed by later failure" still exists, and the antifouling effect after 180 days is lower than that of Example 2 of this invention. This proves that hydrophilic modification of the microcapsule surface is the technological basis for ensuring the stability of the intelligent controlled-release function and achieving long-term antifouling.

[0055] It will be apparent to those skilled in the art that the present invention is not limited to the details of the exemplary embodiments described above, and that the invention can be implemented in other specific forms without departing from its spirit or essential characteristics. Therefore, the embodiments should be considered in all respects as exemplary and non-limiting, and the scope of the invention is defined by the appended claims rather than the foregoing description. Thus, all variations falling within the meaning and scope of equivalents of the claims are intended to be included within the present invention. No markings in the claims should be construed as limiting the scope of the claims.

Claims

1. A method for preparing a composite material for synergistic protection against barnacle attachment to a ship's hull, characterized in that, Includes the following steps: (1) Aramid and polyethylene terephthalate are made into blended yarns, which are woven into high-density woven fabrics. The woven fabrics are desized, scouring, cleaned and dried, and then subjected to high-temperature and high-pressure calendering to obtain a surface modified layer. (2) Modified microcapsules carrying antifouling agents are blended with polycaprolactone as the skin layer material, and the above-mentioned blended yarn is used as the core layer material. Skin-core composite fibers are prepared by skin-core composite spinning, and the fibers are woven into fabric to form a slow-release antifouling layer. (3) The slow-release antifouling layer fabric obtained in step (2) is laminated with the surface modified layer obtained in step (1), and the two layers are bonded at the contact point by hot rolling micro-dot bonding process to obtain a protective barnacle attachment hull composite material.

2. The method for preparing the synergistic protective barnacle-attached hull composite material according to claim 1, characterized in that, The high-temperature and high-pressure calendering process in step (1) is performed using a three-roll calender, with the upper roll temperature at 120~140℃ and the pressure at 20~30 kg / cm². 2 The processing speed is 10~20m / min.

3. The preparation method of the synergistic protective barnacle-attached hull composite material according to claim 1, characterized in that, The weight ratio of the modified microcapsules to the biodegradable polyester in step (2) is 1:(18-21).

4. The method for preparing the synergistic protective barnacle-attached hull composite material according to claim 1, characterized in that, The core-sheath composite spinning process in step (2) adopts zoned temperature control, wherein: the processing and conveying temperature of the sheath material is 100~140℃, the final temperature of the core-sheath composite spinning assembly is 180~220℃, and the residence time in the high temperature zone of 180~220℃ is 0.5~3s.

5. The method for preparing the synergistic protective barnacle-attached hull composite material according to claim 1, characterized in that, The modified microcapsules in step (2) are prepared by first preparing pre-modified microcapsules with antifouling agent and polylactic acid-glycolic acid copolymer, and then modifying the surface of the pre-modified microcapsules with chitosan solution.

6. The method for preparing the synergistic protective barnacle-attached hull composite material according to claim 5, characterized in that, The pre-modified microcapsules have a particle size of 0.1~3 μm and a wall thickness of 1~3 μm. After being modified with chitosan, the modified microcapsules have a particle size of 0.12~3.1 μm and a chitosan coating thickness of 10~50 nm.

7. The method for preparing the synergistic protective barnacle-attached hull composite material according to claim 1, characterized in that, The antifouling agent is one of 1,4,2-oxathiazine-4-oxide and natural alum.

8. The method for preparing the synergistic protective barnacle-attached hull composite material according to claim 1, characterized in that, In step (1), the warp density of the high-density woven fabric is 42 threads / cm, the weft density is 40 threads / cm, and the yarn gap is controlled at 0.07~0.09mm.

9. The method for preparing the synergistic protective barnacle-attached hull composite material according to claim 1, characterized in that, In step (2), the diameter of the composite fiber is 30 μm and the thickness of the sheath layer of the composite fiber is 6~9 μm.

10. The method for preparing the synergistic protective barnacle-attached hull composite material according to claim 1, characterized in that, The hot rolling micro-dot bonding process parameters in step (3) are: the roll temperature of the hot rolling mill is 170~190℃, the pressure is 0.25~0.35MPa, and the contact time is 1~2s.

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