A water-based antifouling coating and its application method

Abstract

This invention provides a water-based antifouling coating comprising the following components A and B. Component A includes the following components by weight: 30-35 parts water-based hydroxyl acrylic resin, 15-20 parts water-based polycarbonate-type polyurethane dispersion, 8-10 parts water-based polyester-type polyurethane dispersion, 8-12 parts polyether-b-poly(N-vinylcaprolactam)-b-polyacrylic acid triblock copolymer, 3-5 parts hydroxyl-terminated PDMS emulsion, 1.5-2.5 parts filler, 2.5-3.5 parts additives, and 15-22 parts deionized water. Component B includes the following components by weight: 8-10 parts curing agent and 3-5 parts propylene glycol methyl ether acetate. This invention provides a water-based coating that possesses broad-spectrum, long-lasting, and environmentally friendly antifouling properties, as well as good mechanical strength and application performance.

Description

Technical Field

[0001] This invention relates to the field of functional coatings, specifically to a water-based antifouling coating and its application method. Background Technology

[0002] Water-based coatings, using water as the dispersion medium, offer significant advantages such as low VOC content, safety, and zero pollution, making them a crucial development direction for the coatings industry. In fields such as shipbuilding, marine engineering, bridges, pipelines, building facades, and biomedical equipment, surface biofouling is a long-standing problem, leading to increased energy consumption, accelerated corrosion, shortened lifespan, and higher maintenance costs. Therefore, developing efficient and environmentally friendly water-based antifouling coatings is of significant practical importance.

[0003] Currently, the main technical routes for waterborne antifouling coatings include: (1) release-type antifouling coatings, which use cuprous oxide, organotin (which has been banned) or other organic bactericides to slowly release toxic substances in seawater to kill attached organisms. However, such coatings pose a potential hazard to non-target organisms and have limited long-term effectiveness; (2) fouling-desorption type antifouling coatings, which are mainly based on organosilicon or fluorocarbon resins. They utilize their low surface energy and hydrophobic properties to make it difficult for fouling organisms to attach or easy to detach under fluid shear force. However, pure organosilicon coatings have poor mechanical strength, weak adhesion, are easily scratched and damaged, and have poor antifouling effect under static or low-speed flow conditions; (3) photocatalytic antifouling coatings, such as those using nano-TiO2, ZnO and other photocatalytic materials to generate reactive oxygen species (ROS) under ultraviolet light irradiation to degrade organic pollutants and kill microorganisms. However, they have poor response to visible light and the coating is prone to aging and degradation during the photocatalytic process.

[0004] To overcome the limitations of single antifouling mechanisms, researchers have attempted to combine multiple antifouling strategies, such as combining low surface energy components with photocatalytic materials or bactericides, in order to achieve synergistic antifouling effects. However, such composite coatings still face many challenges in practical applications: First, the coating inevitably suffers mechanical damage during use, and the resulting microcracks and breaks become "hot spots" for biofouling adhesion, severely compromising the integrity of the coating and the durability of its antifouling function. Therefore, endowing antifouling coatings with self-healing capabilities, enabling them to automatically repair micro-damage, is crucial for extending coating life and maintaining long-term antifouling performance. Existing self-healing coatings mainly achieve this by microencapsulating repair agents or introducing dynamic polymer networks based on reversible covalent / non-covalent bonds such as hydrogen bonds, disulfide bonds, and Diels-Alder bonds.

[0005] On the other hand, achieving the integration of efficient self-healing and antifouling functions in water-based systems requires addressing the compatibility issues of the resin matrix. Waterborne hydroxyl acrylic resins and waterborne polyurethane dispersions are commonly used components in waterborne two-component polyurethane coatings. The former provides hardness and weather resistance, while the latter provides flexibility and abrasion resistance. However, simple blending of the two often leads to poor system compatibility or uneven crosslinking density, affecting the overall mechanical properties and self-healing efficiency of the coating. Therefore, designing a waterborne coating that combines broad-spectrum, long-lasting, and environmentally friendly antifouling properties with good mechanical strength and application performance remains a pressing technical challenge in this field. Summary of the Invention

[0006] Technical problem to be solved: The purpose of this invention is to provide a water-based antifouling coating, which, through the design of temperature-sensitive / pH dual-responsive triblock copolymer and resin compounding, yields a water-based coating with excellent antifouling performance, good mechanical strength, and good application performance.

[0007] Technical solution: A water-based antifouling coating, comprising component A and component B, wherein component A comprises the following components in parts by weight: 30-35 parts of waterborne hydroxyl acrylic resin 15-20 parts of waterborne polycarbonate polyurethane dispersion 8-10 parts of waterborne polyester polyurethane dispersion 8-12 parts of polyether-b-poly(N-vinylcaprolactam)-b-polyacrylic acid triblock copolymer 3-5 parts of hydroxyl-terminated PDMS emulsion 1.5 to 2.5 parts of filler 2.5 to 3.5 parts of auxiliary agent 15-22 parts deionized water; Component B comprises the following components in parts by weight: 8-10 parts of curing agent 3-5 parts of propylene glycol methyl ether acetate.

[0008] Preferably, the waterborne hydroxyl acrylic resin includes a low-hydroxyl-value waterborne hydroxyl acrylic resin and a high-hydroxyl-value waterborne hydroxyl acrylic resin, wherein the hydroxyl value of the low-hydroxyl-value waterborne hydroxyl acrylic resin is not higher than 85 mgKOH / g, and the hydroxyl value of the high-hydroxyl-value waterborne hydroxyl acrylic resin is not lower than 110 mgKOH / g; the mass ratio of the low-hydroxyl-value waterborne hydroxyl acrylic resin to the high-hydroxyl-value waterborne hydroxyl acrylic resin is 22~28:6~8; The filler is a mixture of g-C3N4 / TiO2 heterojunction particles and nano-silica particles, with a mass ratio of 3:2. The additives include wetting and dispersing agents, leveling agents, defoamers, and light stabilizers, wherein the wetting and dispersing agent is at least one of BYK-190, BYK-181, and TEGO® Dispers 755 W; The leveling agent is at least one of BYK-333, BYK-346, TEGO® Glide 410, and TEGO® Glide 440; The defoamer is at least one of BYK-024, BYK-028, TEGO® Foamex 822, and TEGO® Foamex 810; The light stabilizer is at least one of Tinuvin® 292, Tinuvin® 384-2, Tinuvin® 5333-DW, and Chimassorb® 119 FL.

[0009] Preferably, the curing agent includes an aqueous HDI trimer curing agent and an aqueous IPDI trimer curing agent, wherein the mass ratio of the aqueous HDI trimer curing agent to the aqueous IPDI trimer curing agent is 55:25.

[0010] Preferably, the preparation method of the polyether-b-poly(N-vinylcaprolactam)-b-polyacrylic acid triblock copolymer is as follows: S1. Dissolve the terminal amino polyether in DCM, stir until homogeneous, add 4-cyano-4-(thiobenzoyl)valerate and 4-dimethylaminopyridine, stir under nitrogen protection, and cool to 0~5°C in an ice-water bath. S2. Dissolve N,N'-dicyclohexylcarbodiimide in DCM and slowly add it dropwise to the mixture in step S1. React first in ice water and then at room temperature. Filter to remove DCM, and finally remove DCM by vacuum distillation. Recrystallize and purify with a mixed solvent of n-hexane / diethyl ether and dry under vacuum to obtain a viscous liquid, which is intermediate product 1. S3. Dissolve intermediate product 1 prepared in S2 and N-vinylcaprolactam in anhydrous DMF, add initiator AIBN, react under nitrogen protection, terminate the reaction by exposure to air, precipitate by adding cold n-hexane, filter, wash three times with n-hexane, and dry under vacuum to obtain intermediate product 2. S4. Dissolve intermediate product 2 in anhydrous DMF and stir to dissolve. Add purified acrylic acid and stir to mix evenly. Then add initiator AIBN. After deoxygenation by freeze-thaw cycle, react in an oil bath under nitrogen protection for a certain period of time to obtain polyether-b-poly(N-vinylcaprolactam)-b-polyacrylic acid triblock copolymer.

[0011] Preferably, the molar ratio of the terminal amino polyether, 4-cyano-4-(thiobenzoyl)valerate, N,N'-dicyclohexylcarbodiimide and 4-dimethylaminopyridine is 0.8~1:2~2.4:2~2.4:0.2~0.24, and the reaction time in S2 is 1~3h in an ice-water bath or 20~30h at room temperature.

[0012] Preferably, the intermediate product 1, N-vinylcaprolactam and AIBN have a mass ratio of 10:12~13:0.14~0.15, and the reaction is carried out at a temperature of 68~74°C and a time of 8~12h under nitrogen protection.

[0013] Preferably, the intermediate product 2 has a mass ratio of acrylic acid to AIBN of 10:1.5~1.7:0.07~0.08, and the reaction is carried out in an oil bath at a temperature of 68~74°C for 8~12 hours.

[0014] Preferably, the preparation method of the g-C3N4 / TiO2 heterojunction particles includes the following steps: g-C3N4 was added to anhydrous ethanol and ultrasonically dispersed to obtain a suspension with a concentration of 2-5 wt. Tetrabutyl titanate was added to anhydrous ethanol, and glacial acetic acid was added dropwise. The volume ratio of tetrabutyl titanate, anhydrous ethanol and glacial acetic acid was 4.5:3:20. The mixture was stirred until homogeneous to obtain a transparent solution. The transparent solution was added dropwise to the suspension. After the addition was complete, the mixture was stirred for 1-2 hours. Then, deionized water was slowly added dropwise. After the addition was complete, the mixture was stirred for 3-4 hours. Finally, a hydrothermal reaction was carried out at a temperature of 180℃ for 12 hours. The product obtained from the reaction was washed, filtered, dried, and ground to obtain g-C3N4 / TiO2 heterojunction particles.

[0015] The application method of the above-mentioned water-based antifouling coating includes the following steps: Step 1: Mix and stir the waterborne hydroxyl acrylic resin, waterborne polycarbonate polyurethane dispersion and waterborne polyester polyurethane dispersion evenly to form a stable emulsion base. Step 2: Add the polyether-b-poly(N-vinylcaprolactam)-b-polyacrylic acid triblock copolymer, filler and hydroxyl-terminated PDMS emulsion to the emulsion base in sequence, stir evenly to form a stable slurry; Step 3: Add the additives to the stabilized slurry in sequence, stir evenly, and finally add water. Stir evenly and then filter through a 100-200 mesh screen to obtain component A. Step 4: Mix the curing agent and propylene glycol methyl ether acetate, then filter through a 100-200 mesh screen to obtain component B; Step 5: Mix component A and component B at a mass ratio of 100:8~10, spray the mixture onto the substrate, and allow it to dry.

[0016] Beneficial effects: This invention has the following advantages: The polyether-b-poly(N-vinylcaprolactam)-b-polyacrylic acid triblock copolymer used in this invention exhibits a low critical solution temperature (LCST) of approximately 32°C, characterized by its thermosensitive properties. When the ambient temperature is below the LCST, the PNVCL segment is in a hydrophilic extended state, resulting in a moderately hydrophilic coating surface that facilitates the removal of inorganic pollutants by rainwater. When the ambient temperature is above the LCST, the PNVCL segment hydrophobically contracts, pushing the polyether segment to the surface, transforming the coating into a hydrophobic state and effectively repelling organic pollutants. The polyacrylic acid (PAA) segment at the end of the triblock copolymer contains carboxyl functional groups, whose ionization state changes with the ambient pH. When acidic pollutants come into contact with the coating surface, the local pH decreases, the carboxyl group ionizes, and the hydrophobicity increases, forming a hydrophobic barrier to prevent the penetration of acidic substances. When alkaline pollutants come into contact with the coating, the carboxyl group ionizes, increasing the hydrophilicity and facilitating the removal of alkaline substances by water. This pH-responsive characteristic allows the coating to produce differentiated surface responses to different types of pollutants, improving the accuracy and efficiency of antifouling. The g-C3N4 / TiO2 heterojunction particles used in this invention are photocatalytic materials. When there is sunlight during the day, the photocatalytic activity is dominant, which degrades the attached organic pollutants and further improves the antifouling effect of the coating. The hydroxyl-terminated PDMS emulsion added in this invention allows its hydroxyl groups to participate in the polyurethane curing reaction, anchoring PDMS segments within the coating network while preserving the migration ability of the PDMS backbone. During coating curing, PDMS segments spontaneously migrate and accumulate to the surface, forming low surface energy micro-regions that synergistically enhance the hydrophobic repulsion effect with the temperature-sensitive polymer. The polycarbonate diol soft segments in the waterborne polycarbonate-type polyurethane dispersion exhibit superior hydrolysis resistance and weather resistance compared to polyester-type polyurethane. Its molecular structure does not contain easily hydrolyzed ester bonds, enabling it to maintain its mechanical properties over long periods in humid environments. Combined with the polyester-type polyurethane dispersion, it improves adhesion, forming a composite network that combines excellent hydrolysis resistance and adhesion. In this invention, the low-hydroxyl-value waterborne hydroxyl acrylic resin has a low hydroxyl density on its molecular chain, resulting in a moderate crosslinking density after curing and a large degree of freedom of movement for its molecular chain segments. This endows the coating with excellent flexibility, impact resistance, and adhesion to the substrate, enabling it to adapt to the thermal expansion and contraction and slight deformation of the substrate, preventing the coating from cracking and peeling. The high-hydroxyl-value waterborne hydroxyl acrylic resin provides more reaction sites, resulting in a higher crosslinking density after curing. This significantly improves the surface hardness and corrosion resistance of the coating, allowing it to withstand daily wiping, cleaning, and chemical contact. The mass ratio of low-hydroxyl-value resin to high-hydroxyl-value resin is controlled within the range of 22~28:6~8. Through the synergistic effect of the two, the coating simultaneously possesses excellent flexibility, adhesion, hardness, and abrasion resistance, avoiding the contradiction that a single resin cannot achieve all these properties, and meeting the stringent requirements for comprehensive mechanical properties of external surface protective coatings. Detailed Implementation

[0017] The present invention will be further described below with reference to embodiments. These embodiments are illustrative of the present invention, but the present invention is not limited to these embodiments: Low hydroxyl value waterborne hydroxyl acrylic resin, Bayhydrol® A 2470 (Covestro), hydroxyl value 85 mgKOH / g. High hydroxyl value waterborne hydroxyl acrylic resin, Bayhydrol® A 2645 (Covestro), hydroxyl value 110 mgKOH / g. Waterborne polycarbonate-based polyurethane dispersion, Bayhydrol® UH XP 2648 (Covestro), 40% solids content. Waterborne polyester polyurethane dispersion, Bayhydrol® U 2757 (Covestro), 38% solids content. Hydroxyl-terminated PDMS emulsion, Waterborne HDI trimer curing agent, Bayhydur® 304 (Covestro), NCO content 17.5%, solids content 100%. Waterborne IPDI trimer curing agent, Bayhydur® 401-70 (Covestro), NCO content 12.0%, solids content 70%. Amino-terminated polyether (Huntsman), Mn=2000, double-terminated -NH2 N-Vinylcaprolactam, Sigma-Aldrich, purity >98%. Acrylic acid, Aladdin, purity >99%, 4-Cyano-4-(Thiobenzoyl)valerate, Sigma-Aldrich, purity >98%, N,N'-Dicyclohexylcarbodiimide, Aladdin, purity >99%. Dimethylaminopyridine, Aladdin, purity >99%.

[0018] Example 1

[0019] The preparation method of g-C3N4 / TiO2 heterojunction particles includes the following steps: g-C3N4 was added to anhydrous ethanol and ultrasonically dispersed to obtain a suspension with a concentration of 2wt. Tetrabutyl titanate was added to anhydrous ethanol, and glacial acetic acid was added dropwise. The volume ratio of tetrabutyl titanate, anhydrous ethanol and glacial acetic acid was 4.5:3:20. The mixture was stirred until homogeneous to obtain a transparent solution. The transparent solution was added dropwise to the suspension. After the addition was complete, the mixture was stirred for 1 hour. Then, deionized water was slowly added dropwise. After the addition was complete, the mixture was stirred for 3 hours. Finally, a hydrothermal reaction was carried out at a temperature of 180℃ for 12 hours. The product obtained from the reaction was washed, filtered, dried, and ground to obtain g-C3N4 / TiO2 heterojunction particles.

[0020] Example 2

[0021] The preparation method of g-C3N4 / TiO2 heterojunction particles includes the following steps: g-C3N4 was added to anhydrous ethanol and ultrasonically dispersed to obtain a suspension with a concentration of 5 wt. Tetrabutyl titanate was added to anhydrous ethanol, and glacial acetic acid was added dropwise. The volume ratio of tetrabutyl titanate, anhydrous ethanol and glacial acetic acid was 4.5:3:20. The mixture was stirred until homogeneous to obtain a transparent solution. The transparent solution was added dropwise to the suspension. After the addition was complete, the mixture was stirred for 2 hours. Then, deionized water was slowly added dropwise. After the addition was complete, the mixture was stirred for 4 hours. Finally, a hydrothermal reaction was carried out at a temperature of 180℃ for 12 hours. The product obtained from the reaction was washed, filtered, dried, and ground to obtain g-C3N4 / TiO2 heterojunction particles.

[0022] Example 3

[0023] The preparation method of polyether-b-poly(N-vinylcaprolactam)-b-polyacrylic acid triblock copolymer is as follows: S1. Dissolve the amino-terminated polyether in DCM, stir until homogeneous, add 4-cyano-4-(thiobenzoyl)valerate and 4-dimethylaminopyridine, stir under nitrogen protection, and cool to 0°C in an ice-water bath. S2. Dissolve N,N'-dicyclohexylcarbodiimide in DCM and slowly add it dropwise to the mixture in step S1. The molar ratio of terminal amino polyether, 4-cyano-4-(thiobenzoyl)valerate, N,N'-dicyclohexylcarbodiimide and 4-dimethylaminopyridine is 0.8:2:2:0.2. React in ice water for 1 h and then at room temperature for 30 h. Filter to remove DCU, and finally remove DCM by vacuum distillation. Recrystallize and purify with a hexane / diethyl ether mixed solvent, and dry under vacuum to obtain a viscous liquid, which is intermediate product 1. S3. Dissolve intermediate product 1 and N-vinylcaprolactam prepared in S2 in anhydrous DMF, add initiator AIBN, the mass ratio of intermediate product 1, N-vinylcaprolactam and AIBN is 10:12:0.14, react under nitrogen protection, the reaction temperature is 68℃ and the time is 12h, the reaction is terminated by exposure to air, cold n-hexane is added dropwise to precipitate, filtered, washed 3 times with n-hexane, and dried under vacuum to obtain intermediate product 2; S4. Dissolve intermediate product 2 in anhydrous DMF and stir until dissolved. Add purified acrylic acid and stir until homogeneous. Then add initiator AIBN. The mass ratio of intermediate product 2, acrylic acid and AIBN is 10:1.5:0.07. After deoxygenation by freeze-thaw cycle, react in an oil bath under nitrogen protection for 8 hours at 68°C. The purified product is a polyether-b-poly(N-vinylcaprolactam)-b-polyacrylic acid triblock copolymer.

[0024] Example 4

[0025] The preparation method of polyether-b-poly(N-vinylcaprolactam)-b-polyacrylic acid triblock copolymer is as follows: S1. Dissolve the amino-terminated polyether in DCM, stir until homogeneous, add 4-cyano-4-(thiobenzoyl)valerate and 4-dimethylaminopyridine, stir under nitrogen protection, and cool to 5°C in an ice-water bath. S2. Dissolve N,N'-dicyclohexylcarbodiimide in DCM and slowly add it dropwise to the mixture in step S1. The molar ratio of terminal amino polyether, 4-cyano-4-(thiobenzoyl)valerate, N,N'-dicyclohexylcarbodiimide and 4-dimethylaminopyridine is 1:2.4:2.4:0.24. React in ice water for 3 h and then at room temperature for 20 h. Filter to remove DCU, and finally remove DCM by vacuum distillation. Recrystallize and purify with a hexane / diethyl ether mixed solvent, and dry under vacuum to obtain a viscous liquid, which is intermediate product 1. S3. Dissolve intermediate product 1 and N-vinylcaprolactam prepared in S2 in anhydrous DMF, add initiator AIBN, the mass ratio of intermediate product 1, N-vinylcaprolactam and AIBN is 10:13:0.15, react under nitrogen protection, the reaction temperature is 74℃ and the time is 8h, terminate the reaction by exposure to air, precipitate by adding cold n-hexane dropwise, filter, wash 3 times with n-hexane, and dry under vacuum to obtain intermediate product 2; S4. Dissolve intermediate product 2 in anhydrous DMF and stir until dissolved. Add purified acrylic acid and stir until homogeneous. Then add initiator AIBN. The mass ratio of intermediate product 2, acrylic acid and AIBN is 10:1.7:0.08. After deoxygenation by freeze-thaw cycle, react in an oil bath under nitrogen protection for 12 hours at 68°C. The resulting product is a polyether-b-poly(N-vinylcaprolactam)-b-polyacrylic acid triblock copolymer.

[0026] Example 5

[0027] The preparation method of polyether-b-poly(N-vinylcaprolactam)-b-polyacrylic acid triblock copolymer is as follows: S1. Dissolve the amino-terminated polyether in DCM, stir until homogeneous, add 4-cyano-4-(thiobenzoyl)valerate and 4-dimethylaminopyridine, stir under nitrogen protection, and cool to 0°C in an ice-water bath. S2. Dissolve N,N'-dicyclohexylcarbodiimide in DCM and slowly add it dropwise to the mixture in step S1. The molar ratio of terminal amino polyether, 4-cyano-4-(thiobenzoyl)valerate, N,N'-dicyclohexylcarbodiimide and 4-dimethylaminopyridine is 0.88:2.2:2.2:0.2. React in ice water for 2 hours and then at room temperature for 25 hours. Filter to remove DCU, and finally remove DCM by vacuum distillation. Recrystallize and purify with a hexane / diethyl ether mixed solvent, and dry under vacuum to obtain a viscous liquid, which is intermediate product 1. S3. Dissolve intermediate product 1 and N-vinylcaprolactam prepared in S2 in anhydrous DMF, add initiator AIBN, the mass ratio of intermediate product 1, N-vinylcaprolactam and AIBN is 10:12.4:0.146, react under nitrogen protection, the reaction temperature is 70℃ and the time is 10h, the reaction is terminated by exposure to air, cold n-hexane is added dropwise to precipitate, filtered, washed 3 times with n-hexane, and dried under vacuum to obtain intermediate product 2; S4. Dissolve intermediate product 2 in anhydrous DMF and stir until dissolved. Add purified acrylic acid and stir until homogeneous. Then add initiator AIBN. The mass ratio of intermediate product 2, acrylic acid and AIBN is 10:1.6:0.078. After deoxygenation by freeze-thaw cycle, react in an oil bath under nitrogen protection for 10 hours at 70°C. The purified product is a polyether-b-poly(N-vinylcaprolactam)-b-polyacrylic acid triblock copolymer.

[0028] Example 6

[0029] A water-based antifouling coating comprises component A and component B, wherein component A includes the following components in parts by weight: 30 parts of waterborne hydroxyl acrylic resin, 15 parts of waterborne polycarbonate polyurethane dispersion, 8 parts of waterborne polyester polyurethane dispersion, 8 parts of polyether-b-poly(N-vinylcaprolactam)-b-polyacrylic acid triblock copolymer prepared in Example 3, 3 parts of hydroxyl-terminated PDMS emulsion, 1.5 parts of filler, 0.8 parts of wetting and dispersing agent BYK-190, 0.7 parts of leveling agent BYK-333, 0.5 parts of defoamer BYK-024, 0.5 parts of light stabilizer Tinuvin® 292, and 15 parts of deionized water; Component B comprises the following components in parts by weight: 10 parts curing agent, 3 parts propylene glycol methyl ether acetate; The waterborne hydroxyl acrylic resin is a low-hydroxyl-value waterborne hydroxyl acrylic resin and a high-hydroxyl-value waterborne hydroxyl acrylic resin in a mass ratio of 22:6. The filler is a mixture of g-C3N4 / TiO2 heterojunction particles and nano-silica particles prepared in Example 1, with a mass ratio of 3:2. The curing agent is a water-based HDI trimer curing agent and a water-based IPDI trimer curing agent with a mass ratio of 55:25; The application method of water-based antifouling coatings includes the following steps: Step 1: Mix and stir the waterborne hydroxyl acrylic resin, waterborne polycarbonate polyurethane dispersion and waterborne polyester polyurethane dispersion evenly to form a stable emulsion base. Step 2: Add the polyether-b-poly(N-vinylcaprolactam)-b-polyacrylic acid triblock copolymer, filler and hydroxyl-terminated PDMS emulsion to the emulsion base in sequence, stir evenly to form a stable slurry; Step 3: Add the additives to the stabilized slurry in sequence, stir evenly, and finally add water. Stir evenly and then filter through a 100-mesh screen to obtain component A. Step 4: Mix the curing agent and propylene glycol methyl ether acetate, then filter through a 100-mesh screen to obtain component B; Step 5: Mix component A and component B at a mass ratio of 100:8, spray the mixture onto the substrate, and allow it to dry.

[0030] Example 7

[0031] A water-based antifouling coating comprises component A and component B, wherein component A includes the following components in parts by weight: The mixture consists of 35 parts of waterborne hydroxyl acrylic resin, 20 parts of waterborne polycarbonate polyurethane dispersion, 10 parts of waterborne polyester polyurethane dispersion, 12 parts of polyether-b-poly(N-vinylcaprolactam)-b-polyacrylic acid triblock copolymer prepared in Example 4, 5 parts of hydroxyl-terminated PDMS emulsion, 2.5 parts of filler, 0.6 parts of wetting and dispersing agent BYK-190, 0.8 parts of leveling agent BYK-333, 0.7 parts of defoamer BYK-024, 0.8 parts of light stabilizer Tinuvin® 292, and 22 parts of deionized water. Component B comprises the following components in parts by weight: 10 parts curing agent, 5 parts propylene glycol methyl ether acetate; The waterborne hydroxyl acrylic resin is a low-hydroxyl-value waterborne hydroxyl acrylic resin and a high-hydroxyl-value waterborne hydroxyl acrylic resin with a mass ratio of 28:8. The filler is a mixture of g-C3N4 / TiO2 heterojunction particles and nano-silica particles prepared in Example 2, with a mass ratio of 3:2. The curing agent is a water-based HDI trimer curing agent and a water-based IPDI trimer curing agent with a mass ratio of 55:25; The application method of water-based antifouling coatings includes the following steps: Step 1: Mix and stir the waterborne hydroxyl acrylic resin, waterborne polycarbonate polyurethane dispersion and waterborne polyester polyurethane dispersion evenly to form a stable emulsion base. Step 2: Add the polyether-b-poly(N-vinylcaprolactam)-b-polyacrylic acid triblock copolymer, filler and hydroxyl-terminated PDMS emulsion to the emulsion base in sequence, stir evenly to form a stable slurry; Step 3: Add the additives to the stabilized slurry in sequence, stir evenly, and finally add water. Stir evenly and then filter through a 100-mesh screen to obtain component A. Step 4: Mix the curing agent and propylene glycol methyl ether acetate, then filter through a 100-mesh screen to obtain component B; Step 5: Mix component A and component B at a mass ratio of 100:10, spray the mixture onto the substrate, and allow it to dry.

[0032] Example 8

[0033] A water-based antifouling coating comprises component A and component B, wherein component A includes the following components in parts by weight: 32 parts of waterborne hydroxyl acrylic resin, 16 parts of waterborne polycarbonate polyurethane dispersion, 8.5 parts of waterborne polyester polyurethane dispersion, 9 parts of polyether-b-poly(N-vinylcaprolactam)-b-polyacrylic acid triblock copolymer (Example 5), 3.5 parts of hydroxyl-terminated PDMS emulsion, 1.8 parts of filler, 0.6 parts of wetting and dispersing agent BYK-190, 0.8 parts of leveling agent BYK-333, 0.7 parts of defoamer BYK-024, 0.9 parts of light stabilizer Tinuvin® 292, and 15 parts of deionized water; Component B comprises the following components in parts by weight: 10 parts curing agent, 3.5 parts propylene glycol methyl ether acetate; The waterborne hydroxyl acrylic resin is a low-hydroxyl-value waterborne hydroxyl acrylic resin and a high-hydroxyl-value waterborne hydroxyl acrylic resin with a mass ratio of 24:6.5. The filler is a mixture of g-C3N4 / TiO2 heterojunction particles and nano-silica particles prepared in Example 2, with a mass ratio of 3:2. The curing agent is a water-based HDI trimer curing agent and a water-based IPDI trimer curing agent with a mass ratio of 55:25; The application method of water-based antifouling coatings includes the following steps: Step 1: Mix and stir the waterborne hydroxyl acrylic resin, waterborne polycarbonate polyurethane dispersion and waterborne polyester polyurethane dispersion evenly to form a stable emulsion base. Step 2: Add the polyether-b-poly(N-vinylcaprolactam)-b-polyacrylic acid triblock copolymer, filler and hydroxyl-terminated PDMS emulsion to the emulsion base in sequence, stir evenly to form a stable slurry; Step 3: Add the additives to the stabilized slurry in sequence, stir evenly, and finally add water. Stir evenly and then filter through a 100-mesh screen to obtain component A. Step 4: Mix the curing agent and propylene glycol methyl ether acetate, then filter through a 100-mesh screen to obtain component B; Step 5: Mix component A and component B at a mass ratio of 100:8, spray the mixture onto the substrate, and allow it to dry.

[0034] Example 9

[0035] A water-based antifouling coating comprises component A and component B, wherein component A includes the following components in parts by weight: The mixture contains 34 parts of waterborne hydroxyl acrylic resin, 18 parts of waterborne polycarbonate polyurethane dispersion, 9.5 parts of waterborne polyester polyurethane dispersion, 11 parts of polyether-b-poly(N-vinylcaprolactam)-b-polyacrylic acid triblock copolymer (Example 5), 4.5 parts of hydroxyl-terminated PDMS emulsion, 2.2 parts of filler, 0.6 parts of wetting and dispersing agent BYK-190, 0.8 parts of leveling agent BYK-333, 0.7 parts of defoamer BYK-024, 0.9 parts of light stabilizer Tinuvin® 292, and 22 parts of deionized water. Component B comprises the following components in parts by weight: 8 parts curing agent, 4.5 parts propylene glycol methyl ether acetate; The waterborne hydroxyl acrylic resin is a low-hydroxyl-value waterborne hydroxyl acrylic resin and a high-hydroxyl-value waterborne hydroxyl acrylic resin with a mass ratio of 26:7.5. The filler is a mixture of g-C3N4 / TiO2 heterojunction particles and nano-silica particles prepared in Example 2, with a mass ratio of 3:2. The curing agent is a water-based HDI trimer curing agent and a water-based IPDI trimer curing agent with a mass ratio of 55:25; The application method of water-based antifouling coatings includes the following steps: Step 1: Mix and stir the waterborne hydroxyl acrylic resin, waterborne polycarbonate polyurethane dispersion and waterborne polyester polyurethane dispersion evenly to form a stable emulsion base. Step 2: Add the polyether-b-poly(N-vinylcaprolactam)-b-polyacrylic acid triblock copolymer, filler and hydroxyl-terminated PDMS emulsion to the emulsion base in sequence, stir evenly to form a stable slurry; Step 3: Add the additives to the stabilized slurry in sequence, stir evenly, and finally add water. Stir evenly and then filter through a 200-mesh screen to obtain component A. Step 4: Mix the curing agent and propylene glycol methyl ether acetate, then filter through a 200-mesh screen to obtain component B; Step 5: Mix component A and component B at a mass ratio of 100:10, spray the mixture onto the substrate, and allow it to dry.

[0036] Example 10

[0037] A water-based antifouling coating comprises component A and component B, wherein component A includes the following components in parts by weight: 33 parts of waterborne hydroxyl acrylic resin, 17 parts of waterborne polycarbonate polyurethane dispersion, 9 parts of waterborne polyester polyurethane dispersion, 10 parts of polyether-b-poly(N-vinylcaprolactam)-b-polyacrylic acid triblock copolymer (Example 5), 4 parts of hydroxyl-terminated PDMS emulsion, 2 parts of filler, 0.6 parts of wetting and dispersing agent BYK-190, 0.8 parts of leveling agent BYK-333, 0.7 parts of defoamer BYK-024, 0.9 parts of light stabilizer Tinuvin® 292, and 18 parts of deionized water; Component B comprises the following components in parts by weight: 8.5 parts curing agent, 4 parts propylene glycol methyl ether acetate; The waterborne hydroxyl acrylic resin is a low-hydroxyl-value waterborne hydroxyl acrylic resin and a high-hydroxyl-value waterborne hydroxyl acrylic resin with a mass ratio of 25:7. The filler is a mixture of g-C3N4 / TiO2 heterojunction particles and nano-silica particles prepared in Example 2, with a mass ratio of 3:2. The curing agent is a water-based HDI trimer curing agent and a water-based IPDI trimer curing agent with a mass ratio of 55:25; The application method of water-based antifouling coatings includes the following steps: Step 1: Mix and stir the waterborne hydroxyl acrylic resin, waterborne polycarbonate polyurethane dispersion and waterborne polyester polyurethane dispersion evenly to form a stable emulsion base. Step 2: Add the polyether-b-poly(N-vinylcaprolactam)-b-polyacrylic acid triblock copolymer, filler and hydroxyl-terminated PDMS emulsion to the emulsion base in sequence, stir evenly to form a stable slurry; Step 3: Add the additives to the stabilized slurry in sequence, stir evenly, and finally add water. Stir evenly and then filter through a 200-mesh screen to obtain component A. Step 4: Mix the curing agent and propylene glycol methyl ether acetate, then filter through a 100-mesh screen to obtain component B; Step 5: Mix component A and component B at a mass ratio of 100:9, spray the mixture onto the substrate, and allow it to dry.

[0038] Comparative Example 1 The difference between Comparative Example 1 and Example 10 is that no polyether-b-poly(N-vinylcaprolactam)-b-polyacrylic acid triblock copolymer was added.

[0039] Comparative Example 2 The difference between Comparative Example 2 and Example 10 is that only a low-hydroxyl-value waterborne hydroxyl acrylic resin was used.

[0040] Comparative Example 3 The difference between Comparative Example 3 and Example 10 is that the waterborne polycarbonate polyurethane dispersion was replaced with a waterborne polyester polyurethane dispersion.

[0041] Comparative Example 4 The difference between Comparative Example 4 and Example 10 is that the hydroxyl-terminated PDMS emulsion is not used.

[0042] Comparative Example 5 The difference between Comparative Example 5 and Example 10 is that the mass ratio of low hydroxyl value waterborne hydroxyl acrylic resin to high hydroxyl value waterborne hydroxyl acrylic resin is 2:1.

[0043] Comparative Example 6 The difference between Comparative Example 6 and Example 10 is that the g-C3N4 / TiO2 heterojunction particles were replaced with ordinary nano-titanium dioxide.

[0044] Performance testing: Performance tests were conducted on Examples 6-10 and Comparative Examples 1-6. In Table 1, adhesion was tested according to GB / T 9286, hardness according to GB / T 6739, and flexibility according to GB / T 6742.

[0045] Table 1

[0046] Water contact angle tests were conducted on Example 10 and Comparative Examples 1 and 4. Table 2 shows the water contact angles at different temperatures.

[0047] Table 2

[0048] The stain resistance of Examples 10 and Comparative Examples 1 and 6 was tested. The tests in Table 3 were conducted according to Method A in GB / T9780. The stain used in the test was carbon black slurry with a pH of 5. After coating, the slurry was irradiated with a UV lamp (365nm, 100W, 10cm away from the solution) for 4 hours. The test results were evaluated using five levels: 0 (no stain), 1 (very slight), 2 (slight), 3 (moderate), and 4 (severe). These levels correspond to the five levels of the basic gray card (GB / T 250): 5, 4, 3, 2, and 1.

[0049] Table 3

[0050] Obviously, the above embodiments are merely illustrative examples for clear explanation and are not intended to limit the implementation. Those skilled in the art will recognize that other variations or modifications can be made based on the above description. It is neither necessary nor possible to exhaustively list all possible implementations here. However, obvious variations or modifications derived therefrom are still within the scope of protection of this invention.

Claims

1. A water-based antifouling coating, characterized in that, It contains the following components A and B, wherein component A comprises the following parts by weight: 30-35 parts of waterborne hydroxyl acrylic resin 15-20 parts of waterborne polycarbonate polyurethane dispersion 8-10 parts of waterborne polyester polyurethane dispersion 8-12 parts of polyether-b-poly(N-vinylcaprolactam)-b-polyacrylic acid triblock copolymer 3-5 parts of hydroxyl-terminated PDMS emulsion 1.5 to 2.5 parts of filler 2.5 to 3.5 parts of auxiliary agent 15-22 parts deionized water; Component B comprises the following components in parts by weight: 8-10 parts of curing agent 3-5 parts of propylene glycol methyl ether acetate.

2. The water-based antifouling coating according to claim 1, characterized in that: The waterborne hydroxyl acrylic resin includes a low-hydroxyl-value waterborne hydroxyl acrylic resin and a high-hydroxyl-value waterborne hydroxyl acrylic resin. The low-hydroxyl-value waterborne hydroxyl acrylic resin has a hydroxyl value of not more than 85 mg KOH / g, and the high-hydroxyl-value waterborne hydroxyl acrylic resin has a hydroxyl value of not less than 110 mg KOH / g. The mass ratio of the low-hydroxyl-value waterborne hydroxyl acrylic resin to the high-hydroxyl-value waterborne hydroxyl acrylic resin is 22~28:6~8. The filler is a mixture of g-C3N4 / TiO2 heterojunction particles and nano-silica particles, with a mass ratio of 3:

2. The additives include wetting and dispersing agents, leveling agents, defoamers, and light stabilizers, wherein the wetting and dispersing agent is at least one of BYK-190, BYK-181, and TEGO® Dispers 755 W; The leveling agent is at least one of BYK-333, BYK-346, TEGO® Glide 410, and TEGO® Glide 440; The defoamer is at least one of BYK-024, BYK-028, TEGO® Foamex 822, and TEGO® Foamex 810; The light stabilizer is at least one of Tinuvin® 292, Tinuvin® 384-2, Tinuvin® 5333-DW, and Chimassorb® 119 FL.

3. The water-based antifouling coating according to claim 1, characterized in that: The curing agent includes an aqueous HDI trimer curing agent and an aqueous IPDI trimer curing agent, with a mass ratio of 55:

25.

4. The water-based antifouling coating according to claim 1, characterized in that: The preparation method of the polyether-b-poly(N-vinylcaprolactam)-b-polyacrylic acid triblock copolymer is as follows: S1. Dissolve the terminal amino polyether in DCM, stir until homogeneous, add 4-cyano-4-(thiobenzoyl)valerate and 4-dimethylaminopyridine, stir under nitrogen protection, and cool to 0~5°C in an ice-water bath. S2. Dissolve N,N'-dicyclohexylcarbodiimide in DCM and slowly add it dropwise to the mixture in step S1. React first in ice water and then at room temperature. Filter to remove DCM, and finally remove DCM by vacuum distillation. Recrystallize and purify with a mixed solvent of n-hexane / diethyl ether and dry under vacuum to obtain a viscous liquid, which is intermediate product 1. S3. Dissolve intermediate product 1 prepared in S2 and N-vinylcaprolactam in anhydrous DMF, add initiator AIBN, react under nitrogen protection, terminate the reaction by exposure to air, precipitate by adding cold n-hexane, filter, wash three times with n-hexane, and dry under vacuum to obtain intermediate product 2. S4. Dissolve intermediate product 2 in anhydrous DMF and stir to dissolve. Add purified acrylic acid and stir to mix evenly. Then add initiator AIBN. After deoxygenation by freeze-thaw cycle, react in an oil bath under nitrogen protection for a certain period of time to obtain polyether-b-poly(N-vinylcaprolactam)-b-polyacrylic acid triblock copolymer.

5. The water-based antifouling coating according to claim 4, characterized in that: The molar ratio of the terminal amino polyether, 4-cyano-4-(thiobenzoyl)valerate, N,N'-dicyclohexylcarbodiimide and 4-dimethylaminopyridine is 0.8~1:2~2.4:2~2.4:0.2~0.

24. The reaction time in S2 is 1~3h in an ice-water bath and 20~30h at room temperature.

6. The water-based antifouling coating according to claim 4, characterized in that: The intermediate product 1 has a mass ratio of N-vinylcaprolactam to AIBN of 10:12~13:0.14~0.

15. The reaction is carried out under nitrogen protection at a temperature of 68~74℃ for 8~12 hours.

7. The water-based antifouling coating according to claim 4, characterized in that: The intermediate product 2 has an acrylic acid to AIBN mass ratio of 10:1.5~1.7:0.07~0.08, and the reaction is carried out in an oil bath at a temperature of 68~74℃ for 8~12h.

8. The water-based antifouling coating according to claim 2, characterized in that: The preparation method of the g-C3N4 / TiO2 heterojunction particles includes the following steps: g-C3N4 was added to anhydrous ethanol and ultrasonically dispersed to obtain a suspension with a concentration of 2-5 wt. Tetrabutyl titanate was added to anhydrous ethanol, and glacial acetic acid was added dropwise. The volume ratio of tetrabutyl titanate, anhydrous ethanol and glacial acetic acid was 4.5:3:

20. The mixture was stirred until homogeneous to obtain a transparent solution. The transparent solution was added dropwise to the suspension. After the addition was complete, the mixture was stirred for 1-2 hours. Then, deionized water was slowly added dropwise. After the addition was complete, the mixture was stirred for 3-4 hours. Finally, a hydrothermal reaction was carried out at a temperature of 180℃ for 12 hours. The product obtained from the reaction was washed, filtered, dried, and ground to obtain g-C3N4 / TiO2 heterojunction particles.

9. The application method of the water-based antifouling coating according to claim 1, characterized in that, Includes the following steps: Step 1: Mix and stir the waterborne hydroxyl acrylic resin, waterborne polycarbonate polyurethane dispersion and waterborne polyester polyurethane dispersion evenly to form a stable emulsion base. Step 2: Add the polyether-b-poly(N-vinylcaprolactam)-b-polyacrylic acid triblock copolymer, filler and hydroxyl-terminated PDMS emulsion to the emulsion base in sequence, stir evenly to form a stable slurry; Step 3: Add the additives to the stabilized slurry in sequence, stir evenly, and finally add water. Stir evenly and then filter through a 100-200 mesh screen to obtain component A. Step 4: Mix the curing agent and propylene glycol methyl ether acetate, then filter through a 100-200 mesh screen to obtain component B; Step 5: Mix component A and component B at a mass ratio of 100:8~10, spray the mixture onto the substrate, and allow it to dry.

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