A surface-modified, enhanced waterborne self-polishing antifouling coating, coating and method of manufacture

Abstract

The application provides a surface-modified enhanced waterborne self-polishing antifouling coating, a coating and a preparation method. The surface-modified enhanced waterborne self-polishing antifouling coating provided by the application comprises an ATRP initiator slurry and an sSI-ATRP reaction solution which are independently packed. The ATRP initiator slurry is coated on the surface of a substrate to obtain a waterborne self-polishing antifouling coating containing an ATRP initiator, and the coating is immersed in the sSI-ATRP reaction solution, so that a special wettability modification of a micron-scale polymer brush on the surface of the coating can be formed by a subsurface-initiated atom transfer radical polymerization (sSI-ATRP) method, and a surface-modified enhanced waterborne self-polishing antifouling coating is obtained. The surface of the waterborne self-polishing antifouling coating is modified by using the special wettability polymer brush, the static antifouling performance of the coating surface is improved, the antifouling effect is long, the method is green and environmentally friendly, and the method has a wide application prospect.

Description

Technical Field

[0001] This invention relates to the field of marine antifouling coating technology, and in particular to a surface-modified and enhanced water-based self-polishing antifouling coating, coating, and preparation method. Background Technology

[0002] Marine biofouling, caused by a large amount of marine life on the surfaces of ships, submarines, offshore platforms, and offshore production equipment, can have serious adverse effects on these facilities. Particularly in the shipping industry, attached biofouling organisms increase hull surface roughness and fuel consumption, accelerate the corrosion of underwater facilities, and shorten their service life. Therefore, effectively preventing marine biofouling is one of the major challenges facing the development of the marine industry, and marine biofouling prevention is of great significance to the development and utilization of marine resources.

[0003] Coating technology is currently the most widely used marine antifouling technology, mainly including self-polishing antifouling technology and fouling release technology. However, ensuring the antifouling capability of various coating technologies under static conditions is a pressing technical challenge (Progress in Organic Coatings 182(2023)107636). Optimizing the composition of the coating film and regulating the interfacial physicochemical properties are the main strategies. For example, Chinese patent ZL106986969A developed a main-chain degradable copper acrylate marine antifouling coating technology, which can self-renew the coating surface through hydrolytic degradation in static seawater, meeting the static antifouling requirements of low-speed ships and marine engineering platforms. However, it contains cuprous oxide and uses excessive amounts of organic solvents, resulting in poor environmental performance. Furthermore, in terms of antifouling and damage resistance, it mainly considers biofouling issues, with little consideration given to physical wear, and the antifouling effect needs improvement.

[0004] In summary, there have been some reports on water-based low surface energy antifouling coatings, but there is an urgent need for an antifouling coating that is effective, more environmentally friendly, more durable, and has a recyclable wear surface. Summary of the Invention

[0005] The purpose of this invention is to provide a surface-modified and enhanced water-based self-polishing antifouling coating, coating layer, and preparation method. This invention offers excellent antifouling performance, is environmentally friendly, provides long-lasting antifouling protection, and allows for the recycling of worn surfaces.

[0006] To achieve the above-mentioned objectives, the present invention provides the following technical solution:

[0007] This invention provides a surface-modified and enhanced water-based self-polishing antifouling coating, comprising separately packaged ATRP initiator slurry and sSI-ATRP reaction solution;

[0008] The raw materials for preparing the ATRP initiator slurry include an aqueous self-polishing emulsion, an aqueous slurry, and a film-forming aid.

[0009] The mass ratio of the aqueous self-polishing emulsion, aqueous slurry, and film-forming aid is (20-50):(30-60):(5-15);

[0010] The aqueous self-polishing emulsion comprises the following raw materials in the indicated mass percentages: 0.5-2% acrylic acid, 10-30% acrylate silicone monomers, 20-50% vinyl unsaturated monomers, 2-5% polymerizable ATRP initiator monomers, 0.5-3% emulsifier, 0.1-2% initiator, 0.01-1% sodium bicarbonate, 0.1-1% pH adjuster, 10-20% rosin, and the balance being water;

[0011] The components of the water-based slurry include antifouling agent, pigments and fillers, bentonite, thickener, dispersant, defoamer and water; the solid content of the water-based slurry is 40% to 55%.

[0012] The components of the sSI-ATRP reaction solution include an alkenyl monomer, 2,2-bipyridine, a catalyst, and a solvent.

[0013] Preferably, the antifouling agent includes one or more of diuron, copper pyrithione, zinc pyrithione, 4,5-dichloro-N-octyl-3-isothiazolinone, capsaicin, allicin, and zineb.

[0014] Preferably, the pigments and fillers include one or more of zinc oxide, mica powder, talc powder, barium oxide, and iron oxide red.

[0015] Preferably, the thickener includes one or more of methylcellulose, hydroxyethylcellulose, and sodium carboxymethylcellulose.

[0016] Preferably, the dispersant includes one or more of PL-20, fluorinated anionic surfactant, BYK156, and BYK152;

[0017] The defoamer includes one or more of BYK025, DAPROAP7010, and 810 defoamers.

[0018] This invention provides a method for preparing the surface-modified and enhanced water-based self-polishing antifouling coating described in the above technical solution. The method for preparing the ATRP initiator slurry includes the following steps:

[0019] Acrylic acid, acrylate monomers, vinyl unsaturated monomers, polymerizable ATRP initiator monomers, emulsifiers, initiators, sodium bicarbonate, pH adjusters, rosin, and water are emulsion polymerized to obtain an aqueous self-polishing emulsion.

[0020] Antifouling agent, pigments and fillers, bentonite, thickener, dispersant, defoamer and water are mixed and ground to obtain water-based slurry;

[0021] The aqueous self-polishing emulsion, aqueous slurry, and film-forming aid are mixed to obtain an ATRP initiator slurry.

[0022] The preparation method of the sSI-ATRP reaction solution includes the following steps: mixing alkenyl monomer, 2,2-bipyridine, catalyst and solvent to obtain the sSI-ATRP reaction solution.

[0023] This invention also provides a method for preparing a surface-modified and enhanced water-based self-polishing antifouling coating, comprising the following steps:

[0024] An ATRP initiator slurry is coated onto the substrate surface to obtain a water-based self-polishing anti-fouling coating.

[0025] The substrate containing the water-based self-polishing antifouling coating is immersed in the sSI-ATRP reaction solution to carry out the sSI-ATRP reaction, thereby obtaining the surface-modified and enhanced water-based self-polishing antifouling coating.

[0026] The sSI-ATRP reaction was carried out at room temperature for 5-60 minutes.

[0027] The present invention also provides a surface-modified and enhanced waterborne self-polishing antifouling coating prepared by the above preparation method, characterized in that it includes a waterborne self-polishing antifouling coating and a polymer brush modified on the surface of the waterborne self-polishing antifouling coating.

[0028] The thickness of the polymer brush is 5–35 μm.

[0029] This invention provides a surface-modified and enhanced waterborne self-polishing antifouling coating, comprising separately packaged ATRP initiator slurry and sSI-ATRP reaction solution; the raw materials for preparing the ATRP initiator slurry include a waterborne self-polishing emulsion, a waterborne slurry, and a film-forming aid; the mass ratio of the waterborne self-polishing emulsion, the waterborne slurry, and the film-forming aid is (20-50):(30-60):(5-15); the waterborne self-polishing emulsion comprises the following raw materials in the following mass percentages: acrylic acid 0.5-2%, acrylate silicone monomers 10-30%. The aqueous slurry comprises 20-50% vinyl unsaturated monomers, 2-5% polymerizable ATRP initiator monomers, 0.5-3% emulsifier, 0.1-2% initiator, 0.01-1% sodium bicarbonate, 0.1-1% pH adjuster, 10-20% rosin, and the balance being water. The aqueous slurry also includes antifouling agents, pigments and fillers, bentonite, thickeners, dispersants, defoamers, and water. The solid content of the aqueous slurry is 40%-55%. The sSI-ATRP reaction solution comprises alkenyl monomers, 2,2-bipyridine, a catalyst, and a solvent. The surface-modified and enhanced aqueous self-polishing antifouling coating provided by this invention comprises an ATRP initiator slurry and an sSI-ATRP reaction solution. In application, an aqueous self-polishing antifouling coating is first prepared on the substrate surface using the ATRP initiator slurry, and then the aqueous self-polishing antifouling coating undergoes an sSI-ATRP reaction using the sSI-ATRP reaction solution to form a polymer brush on the coating surface. This invention innovatively utilizes subsurface-initiated polymer technology to achieve the construction of a micron-scale self-polishing interface with unique wettability. The synergistic effect of interface-stable hydration and self-polishing properties achieves excellent static antifouling performance against marine biofouling. Furthermore, after the interface components degrade due to self-polishing, the atom-transfer radical polymerization initiator copolymerized in the self-polishing backbone can reconstruct the micron-scale unique wettability interface through subsurface-initiated polymerization, ensuring a long static antifouling period. In addition, the surface-modified and enhanced waterborne self-polishing antifouling coating provided by this invention has low VOC content due to its waterborne preparation method, eliminates cuprous oxide antifouling agents, and is environmentally friendly as it contains no TBT.

[0030] Test examples show that the surface-modified and enhanced waterborne self-polishing antifouling coating prepared using the coating described in this invention exhibits an ultra-low water contact angle and excellent antifouling performance. The acrylic silicone resin on the modified coating surface hydrolyzes in seawater and is subsequently exfoliated under the shearing action of seawater, achieving surface self-polishing and demonstrating good self-renewal ability. Simultaneously, the surface-modified polymer brush coating exhibits excellent hydration effect and an ultra-low water contact angle, and the hydration layer formed on the surface enhances antifouling performance. Test Example 2 shows that when the polymer brush modified on the surface of the coating prepared in this invention is ground off and then placed in a monomer solution, repeated, polymerization can be initiated again to modify the polymer brush onto the coating surface, thereby obtaining an ultra-low water contact angle and excellent antifouling performance. This "wear-re-initiation" process can be repeated multiple times. In other words, the ATRP initiator modifies the entire surface and interior of the self-polishing resin. After interfacial wear or self-polishing, even if the surface polymer brush layer is worn away, the initiator inside the coating can still be exposed and re-initiated, thus exhibiting the characteristic of re-initiated polymerization. The water-based self-polishing antifouling coating containing an atom transfer radical polymerization initiator described in this invention, after surface modification with a polymer brush, has a static water contact angle of 55.7°C to 11.1°C, and inhibits the growth and attachment of *Dendrobium nobile* and *Porphyra yezoensis*. Attached Figure Description

[0031] Figure 1 The images show static water contact angle diagrams, with the water contact angle diagrams for samples from Example 1, Example 2, and Example 3 shown from left to right.

[0032] Figure 2 This is a schematic diagram of Example 3, showing how the coating surface was worn and then modified with a superhydrophilic polymer to obtain ultra-low contact angle and excellent antifouling performance.

[0033] Figure 3 Fluorescence images of *Porphyra yezoensis* on the surface of the sample and blank glass slide of the surface-enhanced modified water-based self-polishing antifouling coating in Example 1;

[0034] Figure 4 The images show fluorescence images of *Dysphorus fasciatus* on the surface of a sample of the surface-enhanced modified water-based self-polishing antifouling coating and a blank glass slide, as shown in Example 1. Detailed Implementation

[0035] This invention provides a surface-modified and enhanced water-based self-polishing antifouling coating, comprising separately packaged ATRP initiator slurry and sSI-ATRP reaction solution;

[0036] The raw materials for preparing the ATRP initiator slurry include an aqueous self-polishing emulsion, an aqueous slurry, and a film-forming aid.

[0037] The mass ratio of the aqueous self-polishing emulsion, aqueous slurry, and film-forming aid is (20-50):(30-60):(5-15);

[0038] The aqueous self-polishing emulsion comprises the following raw materials in the indicated mass percentages: 0.5-2% acrylic acid, 10-30% acrylate silicone monomers, 20-50% vinyl unsaturated monomers, 2-5% polymerizable ATRP initiator monomers, 0.5-3% emulsifier, 0.1-2% initiator, 0.01-1% sodium bicarbonate, 0.1-1% pH adjuster, 10-20% rosin, and the balance being water;

[0039] The components of the water-based slurry include antifouling agent, pigments and fillers, bentonite, thickener, dispersant, defoamer and water; the solid content of the water-based slurry is 40% to 55%.

[0040] The components of the sSI-ATRP reaction solution include an alkenyl monomer, 2,2-bipyridine, a catalyst, and a solvent.

[0041] Unless otherwise specified, all raw materials / components used in this invention are commercially available.

[0042] The surface-modified and enhanced waterborne self-polishing antifouling coating provided by this invention includes an independently packaged ATRP initiator slurry; the raw materials for preparing the ATRP initiator slurry include a waterborne self-polishing emulsion, a waterborne slurry, and a film-forming aid. The waterborne self-polishing emulsion, the waterborne slurry, and the film-forming aid are described in detail below.

[0043] The raw materials for preparing the water-based self-polishing emulsion, by weight percentage, include 0.5-2% acrylic acid, preferably 0.5-1%.

[0044] The raw materials for preparing the water-based self-polishing emulsion, by weight percentage, include 10-30% acrylate silicone monomers, preferably 12-20%; the acrylate silicone monomers preferably include one of triisopropylsilyl methacrylate and triisopropylsilyl acrylate, more preferably triisopropylsilyl acrylate. In this invention, the acrylic monomers can regulate the toughness, thermal properties, and mechanical stability of the coating, while the acrylate silicone monomers mainly play a hydrolytic role, regulating the surface renewal of the self-polishing coating, and are an essential component of the water-based self-polishing emulsion.

[0045] The raw materials for preparing the water-based self-polishing emulsion, by mass percentage, include 20-50% vinyl unsaturated monomers, preferably 25-35%; the vinyl unsaturated monomers preferably include at least three selected from methyl methacrylate, butyl acrylate, butyl methacrylate, styrene, hydroxyethyl methacrylate, isobornyl methacrylate, and dodecafluoroheptyl methacrylate, more preferably three, and even more preferably a mixture of methyl methacrylate, butyl acrylate, and styrene; the mass ratio of methyl methacrylate, butyl acrylate, and styrene in the mixture is preferably (10-20):(5-10):(1-10). The combination of soft and hard monomers ensures that the coating has a reasonable hardness and film-forming properties; simultaneously, the combination of three monomers with different glass transition temperatures helps to synthesize a resin with an ideal glass transition temperature.

[0046] The raw materials for preparing the water-based self-polishing emulsion, by mass percentage, include 0.5-3% emulsifier, preferably 0.6-1%; the emulsifier is preferably a reactive emulsifier, and the reactive emulsifier preferably includes at least two of BC-10, JS-20, and RS-710. In this invention, the emulsifier can reduce the surface tension of water and emulsify monomers, which is beneficial to improving the storage stability of the water-based self-polishing antifouling coating. The emulsifier selected in this invention is a reactive emulsifier, which is copolymerized into the main chain of the self-polishing emulsion, ensuring the excellent water resistance of the self-polishing emulsion.

[0047] The raw materials for preparing the aqueous self-polishing emulsion include 0.1-2% initiator, preferably 0.2-0.6%, by mass percentage; in this invention, the initiator preferably includes persulfate initiators, more preferably ammonium persulfate / potassium persulfate.

[0048] The raw materials for preparing the water-based self-polishing emulsion include 0.01-1% sodium bicarbonate, preferably 0.05-0.5%, by mass percentage. In this invention, the sodium bicarbonate can adjust and buffer the pH value of the water-based self-polishing emulsion, which is beneficial to maintaining the stability of the water-based self-polishing emulsion, thereby ensuring that the water-based self-polishing antifouling coating has good stability.

[0049] The raw materials for preparing the water-based self-polishing emulsion, by mass percentage, include 0.1-1% pH adjuster, preferably 0.1-0.5%; in this invention, the pH adjuster preferably includes ammonia or triethylamine, more preferably ammonia, and the mass concentration of the ammonia is preferably 25-28%; this invention utilizes the pH adjuster to adjust the pH value of the water-based self-polishing emulsion, and at the same time, with the buffering effect of sodium bicarbonate on pH adjustment, it is beneficial to ensure that the water-based self-polishing emulsion has excellent stability, thereby improving the stability of the water-based self-polishing antifouling coating; the pH value of the water-based self-polishing emulsion is preferably 6-8, more preferably 7.

[0050] The raw materials for preparing the water-based self-polishing emulsion, by weight percentage, include 2-5% ATRP initiator monomer, preferably 2.5-4%; the ATRP initiator is preferably 2-((2-bromo-2-methylpropionyl)oxy)ethyl methacrylate (HEMA-Br).

[0051] The raw materials for preparing the water-based self-polishing emulsion, by weight percentage, include 10-20% rosin, preferably 14-20%, and the rosin is preferably natural rosin.

[0052] The raw materials for preparing the water-based self-polishing emulsion, by weight percentage, include the remainder water, preferably deionized water.

[0053] In this invention, the components of the aqueous slurry include an antifouling agent, pigments and fillers, bentonite, a thickener, a dispersant, a defoamer, and water; the fineness of the aqueous slurry is preferably ≤50μm; the mass ratio of the antifouling agent to water in the aqueous slurry is preferably (5-10):(20-50); the mass ratio of the pigments and fillers to water is preferably (40-60):(20-50); the mass ratio of the bentonite to water is preferably (1-5):(20-50); the mass ratio of the thickener to water is preferably (0.01-1):(20-50); the mass ratio of the dispersant to water is preferably (5-10):(20-50); and the mass ratio of the defoamer to water is preferably (0.1-1):(20-50). The antifouling agent preferably includes one or more of diuron, copper pyrithione, zinc pyrithione, 4,5-dichloro-N-octyl-3-isothiazolinone, capsaicin, allicin, and zineb, more preferably at least three of diuron, zineb, allicin, capsaicin, and silver. The pigments and fillers preferably include one or more of zinc oxide, mica powder, talc, barium sulfate, and iron oxide red, more preferably a mixture of zinc oxide, barium sulfate, and iron oxide red. The mass ratio of zinc oxide, barium sulfate, and iron oxide red is preferably (1-5):(1-3):(40-50), more preferably (1-3):(1-2):(40-45). The thickener preferably includes one or more of methylcellulose, hydroxyethylcellulose, and sodium carboxymethylcellulose, more preferably sodium carboxymethylcellulose. The dispersant preferably includes one or more of PL-20, fluorinated anionic surfactant, BYK156, and BYK152, and the fluorinated anionic surfactant is preferably SF333; in a specific embodiment of the present invention, the dispersant more preferably includes PL-20, SF333, and BYK156, and the mass ratio of PL-20, SF333, and BYK156 is preferably (1-5):(0.1-1):(1-5); the defoamer preferably includes one or more of BYK025, DAPROAP7010, and 810 defoamer, and more preferably 810 defoamer.

[0054] In this invention, the film-forming aid is preferably one or more of ethylene glycol, propylene glycol, ethylene glycol butyl ether, propylene glycol butyl ether, and 12-ol ester, more preferably one of propylene glycol butyl ether and 12-ol ester.

[0055] In this invention, the mass ratio of the aqueous self-polishing emulsion, the aqueous slurry, and the film-forming aid is (20-50):(30-60):(5-15), preferably (20-30):(30-40):(10-15).

[0056] The surface-modified and enhanced waterborne self-polishing antifouling coating provided by this invention includes an independently packaged sSI-ATRP reaction solution. In this invention, the sSI-ATRP reaction solution comprises an alkenyl monomer, 2,2-bipyridine, a catalyst, and a solvent. The alkenyl monomer is preferably one of hydroxyethyl methacrylate, 3-[N,N-dimethyl-[2-(2-methylprop-2-enoyloxy)ethyl]ammonium]propane-1-sulfonic acid inner salt, potassium propyl methacrylate, and [2-(methacryloyloxy)ethyl]trimethylammonium chloride. Multiple monomers do not perform well in the sSI-ATRP reaction due to competing reactions. The catalyst is preferably a monovalent Cu salt, more preferably CuBr. The mass ratio of the alkenyl monomer, 2,2-bipyridine, and catalyst is preferably (1–10):(0.01–0.1):(0.01–0.1), more preferably (5–8):(0.05–0.1):(0.02–0.05). The solvent of the sSI-ATRP reaction solution is preferably a mixed solvent of water and methanol, wherein the water is preferably deionized water, and the volume ratio of water to methanol in the mixed solvent is preferably (2-4):(1-20), more preferably 2:1.

[0057] This invention provides a method for preparing the surface-modified and enhanced water-based self-polishing antifouling coating described in the above technical solution. The method for preparing the ATRP initiator slurry includes the following steps:

[0058] Acrylic acid, acrylate monomers, vinyl unsaturated monomers, polymerizable ATRP initiator monomers, emulsifiers, initiators, sodium bicarbonate, pH adjusters, rosin, and water are emulsion polymerized to obtain an aqueous self-polishing emulsion.

[0059] Antifouling agent, pigments and fillers, bentonite, thickener, dispersant, defoamer and water are mixed and ground to obtain water-based slurry;

[0060] The aqueous self-polishing emulsion, aqueous slurry, and film-forming aid are mixed to obtain an ATRP initiator slurry.

[0061] The preparation method of the sSI-ATRP reaction solution includes the following steps: mixing alkenyl monomer, 2,2-bipyridine, catalyst and solvent to obtain the sSI-ATRP reaction solution.

[0062] In this invention, the preparation of the aqueous self-polishing emulsion preferably includes the following steps: mixing vinyl unsaturated monomers, acrylic acid, acrylate silicone monomers, a portion of emulsifier, a first portion of water, polymerizable ATRP initiator monomers, and rosin to obtain component A; mixing the remaining initiator and the second portion of water to obtain component B; mixing sodium bicarbonate, the remaining water, component A, and component B for emulsion polymerization; and finally adjusting the pH to 6-8 with a pH adjuster to obtain the aqueous self-polishing emulsion.

[0063] In this invention, when preparing component A in the aqueous self-polishing emulsion, it is preferable to first stir and mix styrene, vinyl unsaturated monomers, acrylic acid, and acrylate silicone monomers, then add a portion of emulsifier, a first portion of water, polymerizable ATRP initiator monomers, and rosin, followed by a second stirring and mixing. Both the first and second stirring and mixing are preferably mechanically stirred. The first stirring and mixing time is preferably 30–60 min, more preferably 30 min, and the second stirring and mixing time is preferably 30–60 min, more preferably 30 min. The stirring speed for the second stirring and mixing is preferably 580–650 r / min, more preferably 600 r / min.

[0064] In this invention, during the preparation of the aqueous self-polishing emulsion, when mixing component A and component B for emulsion polymerization, it is preferable to first mix sodium bicarbonate, the remaining water, a portion of component A, and a portion of component B for a third time by stirring. Then, the resulting mixture is preferably heated to 80-83°C, more preferably 81°C, and the remaining component A is added dropwise over 1 hour, while component B is continuously and uniformly added during this period to ensure uniform polymerization. After the addition is completed, it is preferable to heat to 88-90°C and then maintain the temperature for 1-2 hours, more preferably to heat to 88°C and then maintain the temperature for 1 hour. Finally, the pH is adjusted to 6-8 with a pH adjuster and stirred for 10-20 minutes, more preferably 10 minutes. The aqueous self-polishing emulsion is obtained when the liquid gradually becomes gelatinous. The stirring time for the third mixing is preferably 30-60 min, and the stirring speed is preferably 580-650 r / min, more preferably 600 r / min; the mass ratio of the partial component A to the partial component B is preferably (15-20):(1-1.5), more preferably 18:1.

[0065] In this invention, when preparing the aqueous slurry, it is preferable to first mix water, thickener, defoamer, dispersant, and bentonite, and stir until homogeneous to obtain a stirred system. Then, antifouling agent and pigments / fillers are mixed and added to the stirred system, and the mixture is ground to obtain the aqueous slurry. The grinding method is a conventional technique in the art, and it is preferable to grind the aqueous slurry to a fineness ≤50μm.

[0066] In this invention, when preparing the sSI-ATRP reaction solution, it is preferable to weigh out the alkenyl monomer, dissolve it in a solvent, and stir it evenly to obtain a monomer solution; the stirring time is preferably 10 min, and N2 protection is preferably used during the stirring process; then, 2,2'-bipyridine and the catalyst are added to the monomer solution in sequence and stirred further, while N2 protection is continuously introduced to obtain a dark brown solution, which is the sSI-ATRP reaction solution.

[0067] This invention also provides a method for preparing a surface-modified and enhanced water-based self-polishing antifouling coating, comprising the following steps:

[0068] An ATRP initiator slurry is coated onto the substrate surface to obtain a water-based self-polishing anti-fouling coating.

[0069] The substrate containing the water-based self-polishing antifouling coating is immersed in the sSI-ATRP reaction solution to carry out the sSI-ATRP reaction, thereby obtaining the surface-modified and enhanced water-based self-polishing antifouling coating.

[0070] In this invention, when preparing the water-based self-polishing antifouling coating, the ATRP initiator slurry is preferentially filtered to remove air bubbles and larger particles to obtain a fine ATRP initiator slurry; the filtration method is preferably filter cloth filtration; the mesh size of the filter cloth is preferably 80 mesh. The preparation method of the water-based self-polishing antifouling coating is preferably spraying, and the spraying is preferably performed using a spray gun; after spraying, it is preferably cured at room temperature for 24-48 hours to obtain the water-based self-polishing antifouling coating.

[0071] In this invention, the sSI-ATRP reaction temperature is preferably room temperature, and the reaction time is preferably 5–60 min, more preferably 5–30 min. After the reaction is completed, it is preferable to rinse with deionized water.

[0072] This invention also provides a surface-modified and enhanced waterborne self-polishing antifouling coating prepared by the above-described method, comprising a waterborne self-polishing antifouling coating and a polymer brush modified on the surface of the waterborne self-polishing antifouling coating. In this invention, the polymer brush modified on the surface of the waterborne self-polishing antifouling coating comprises one of hydroxyethyl methacrylate, 3-[N,N-dimethyl-[2-(2-methylprop-2-enoyloxy)ethyl]ammonium]propane-1-sulfonic acid inner salt, potassium propyl methacrylate, and [2-(methacryloyloxy)ethyl]trimethylammonium chloride polymer brush; the thickness of the polymer brush is preferably 5–35 μm.

[0073] The technical solutions of this invention will be clearly and completely described below with reference to the embodiments thereof. Obviously, the described embodiments are only a part of the embodiments of this invention, and not all of them. Based on the embodiments of this invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of this invention.

[0074] Example 1

[0075] Preparation of water-based self-polishing emulsion:

[0076] Weigh out 5 parts styrene, 8 parts butyl acrylate, 15 parts methyl methacrylate, 2 parts acrylic acid, 14 parts triisopropyl acrylate, and stir for 30 min. Add 0.5 parts emulsifier BC-10, 0.3 parts JS-20, 35 parts deionized water, 2 parts ATRP initiator HEMA-Br, and 14 parts rosin. Mechanically stir at 600 r / min for 30 min to obtain a milky white liquid, which is denoted as component A. Weigh out 0.5 parts ammonium persulfate and add 5 parts deionized water, stirring until homogeneous. Component B was obtained uniformly. 0.2 parts sodium bicarbonate, 12 parts deionized water, 18 parts component A, and 1 part component B were added to a round-bottom flask. The mixture was stirred at 600 r / min for 30 min, and then the temperature was gradually increased to 81°C. The remaining component A was added dropwise over 1 hour, while component B was continuously added. After the addition was completed, the temperature was maintained for 1 hour, then increased to 88°C and maintained for another hour. The pH was adjusted to neutral with ammonia water, and the mixture was stirred for 10 min. The liquid gradually formed a gel, resulting in an aqueous self-polishing emulsion.

[0077] Preparation of water-based slurries:

[0078] First, weigh out 25 parts water, 2 parts sodium carboxymethyl cellulose, 0.5 parts 810 defoamer, 2 parts PL-20, 0.5 parts SF333, and 2 parts bentonite. Add zirconium oxide beads and mechanically stir until homogeneous. Then, weigh out 3 parts zineb, 3 parts diuron, 2 parts ZnO, 2 parts barium sulfate, and 48 parts iron oxide red. Mix these ingredients and add them to the above stirring system. Grind the mixture until the fineness is ≤50μm to obtain an aqueous slurry.

[0079] Preparation of water-based self-polishing antifouling coating:

[0080] Weigh out 45 parts of self-polishing emulsion, 47 parts of aqueous slurry, and 12 parts of film-forming aid, including 7 parts of dodecayl alcohol ester and 5 parts of propylene glycol, and mechanically disperse them evenly. Remove air bubbles and larger particles of the slurry using an 80-mesh filter cloth, and finally spray it onto the substrate using a spray gun. Curing at room temperature for 24 hours prepares the aqueous self-polishing coating.

[0081] Preparation of surface-modified and enhanced waterborne self-polishing antifouling coating:

[0082] 33.3 parts of potassium propyl 3-sulfonate methacrylate monomer were weighed and dissolved in a mixed solvent of 44 parts water and 22 parts methanol. The mixture was stirred until homogeneous and then protected with N2 for 10 min. Then, 0.5 parts of 2,2'-bipyridine and 0.2 parts of CuBr were added sequentially to the above solution, and the mixture was stirred further while continuing to be protected with N2, resulting in a dark brown solution. Finally, the substrate coated with the self-polishing coating was placed in the above-prepared solution. After reacting for 5 min, the sample was removed and rinsed with deionized water to prepare a surface-modified and enhanced waterborne self-polishing antifouling coating.

[0083] Example 2

[0084] Preparation of water-based self-polishing emulsion:

[0085] Weigh out 5 parts styrene, 8 parts isobornyl methacrylate, 15 parts dodecafluoroheptyl methacrylate, 2 parts acrylic acid, 14 parts triisopropylsilyl methacrylate and stir for 30 min. Add 0.5 parts emulsifier BC-10, 0.3 parts JS-20, 35 parts deionized water, 2 parts ATRP initiator HEMA-Br, and 20 parts rosin. Mechanically stir at 600 r / min for 30 min to obtain a milky white liquid, which is denoted as component A. Weigh out 0.5 parts potassium persulfate and add 5 parts deionized water. Component B was obtained by stirring the water until homogeneous. 0.2 parts sodium bicarbonate, 12 parts deionized water, 18 parts component A, and 1 part component B were added to a round-bottom flask. The mixture was stirred at 600 r / min for 30 min, and then the temperature was gradually increased to 81°C. The remaining component A was added dropwise over 1 hour, while continuously adding component B. After the addition was complete, the temperature was maintained for 1 hour, then increased to 88°C and maintained for another hour. The pH was adjusted to neutral with triethylamine, and the mixture was stirred for 10 min. The liquid gradually developed a gel-like consistency, resulting in an aqueous self-polishing emulsion.

[0086] Preparation of water-based slurries:

[0087] First, weigh out 25 parts water, 2 parts hydroxyethyl cellulose, 0.5 parts BYK025 defoamer, 2 parts BYK156, 0.5 parts SF333, and 2 parts bentonite. Add zirconium oxide beads and mechanically stir until homogeneous. Then, weigh out 2 parts zineb, 2 parts diuron, 2 parts zinc pyrithione, 2 parts ZnO, 2 parts barium sulfate, and 48 parts iron oxide red. Mix these ingredients and add them to the above stirring system. Grind the mixture until the fineness is ≤50μm to obtain an aqueous slurry.

[0088] Preparation of water-based self-polishing antifouling coating:

[0089] Weigh out 45 parts of self-polishing emulsion, 47 parts of water-based slurry, and 12 parts of film-forming aid, including 7 parts of dodecayl alcohol ester and 5 parts of propylene glycol. Stir the mixture mechanically until homogeneous. Remove air bubbles and larger particles from the slurry using an 80-mesh filter cloth. Finally, spray the mixture onto the substrate using a spray gun and cure it at room temperature for 24 hours to prepare the water-based self-polishing coating.

[0090] Preparation of surface-modified and enhanced waterborne self-polishing antifouling coating:

[0091] 33.3 parts of potassium propyl 3-sulfonate methacrylate monomer were weighed and dissolved in a mixed solvent of 44 parts water and 22 parts methanol. The mixture was stirred until homogeneous and then protected with N2 for 10 min. Then, 0.5 parts of 2,2'-bipyridine and 0.2 parts of CuBr were added sequentially to the above solution, and the mixture was stirred further while continuing to be protected with N2, resulting in a dark brown solution. Finally, the substrate coated with the self-polishing coating was placed in the above-prepared solution. After reacting for 5 min, the sample was removed and rinsed with deionized water to prepare a surface-modified and enhanced waterborne self-polishing antifouling coating.

[0092] Example 3

[0093] A water-based self-polishing antifouling coating was prepared according to the method in Example 1;

[0094] 33.3 parts of potassium propyl 3-sulfonate methacrylate monomer were weighed and dissolved in a mixed solvent of 44 parts water and 22 parts methanol. The mixture was stirred until homogeneous and then protected with N2 for 10 min. Then, 0.5 parts of 2,2'-bipyridine and 0.2 parts of CuBr were added sequentially to the above solution, and the mixture was stirred further while continuing to be protected with N2, resulting in a dark brown solution. Finally, the substrate coated with the self-polishing coating was placed in the above-prepared solution. After reacting for 30 min, the sample was removed and rinsed with deionized water to prepare a surface-modified and enhanced waterborne self-polishing antifouling coating.

[0095] Example 4

[0096] A water-based self-polishing antifouling coating was prepared according to the method in Example 1;

[0097] 33.3 parts of 3-[N,N-dimethyl-[2-(2-methylprop-2-enoyloxy)ethyl]ammonium]propane-1-sulfonic acid inner salt monomer were weighed and dissolved in a mixed solvent of 44 parts water and 22 parts methanol. The mixture was stirred until homogeneous and then protected with N2 for 10 min. Then, 0.5 parts of 2,2'-bipyridine and 0.2 parts of CuBr were added sequentially to the above solution, and the mixture was stirred further while continuously protected with N2, resulting in a dark brown solution. Finally, the substrate coated with the self-polishing coating was placed in the above-prepared solution. After reacting for 30 min, the sample was removed and rinsed with deionized water to prepare a surface-modified and enhanced waterborne self-polishing antifouling coating.

[0098] Performance Characterization

[0099] 1. The static water contact angle of the water-based self-polishing antifouling coating of Example 1, after surface modification with a polymer brush, was 55.7°C. The static water contact angles of the surface-modified and enhanced water-based self-polishing antifouling coatings prepared in Examples 2 and 3 were 35.1°C and 11.1°C, respectively. The results are as follows: Figure 1 As shown, from left to right, the schematic diagrams are of the water contact angles of the samples from Example 1, Example 2, and Example 3.

[0100] 2. The polymer brush modified with the water-based self-polishing antifouling coating of the grafted polymer brush prepared in Example 3 was polished off, and then placed in the reaction monomer solution. This process was repeated, and the water contact angle and antifouling performance of the material surface were measured. The results are as follows: Figure 2 As shown. By Figure 2 It is known that after the polymer brush layer on the coating surface is worn away, the water contact angle increases and the antifouling performance decreases. However, when placed in the monomer solution, polymerization can be initiated again to modify the polymer brush onto the coating surface, thereby obtaining an ultra-low water contact angle and excellent antifouling performance. This "wear-re-initiation" process can be repeated many times.

[0101] 3. Using a blank glass slide as a control, the experimental and control samples prepared in Example 1 were placed in a solution of *Porphyra yezoensis*. After 24 hours, the number of algae on their surfaces was observed under a fluorescence microscope. The results are as follows: Figure 3 As shown, the left side represents the surface of the control sample, and the right side represents the surface of the experimental sample. Figure 3 It can be seen that the density of *Porphyra yezoensis* on the surface of the experimental sample is significantly lower than that of the control sample. This indicates that the surface-modified and enhanced water-based self-polishing antifouling coating provided in Example 1 has an inhibitory effect on the growth and adhesion of *Porphyra yezoensis*.

[0102] 4. Using a blank glass slide as a control, the experimental and control samples prepared in Example 1 were placed in the *Dendrocalamus bisporus* solution. After 24 hours, the number of algae on their surface was observed under a fluorescence microscope. The results are as follows: Figure 4 As shown, the left side represents the surface of the control sample, and the right side represents the surface of the experimental sample. Figure 4 It can be seen that the density of *Dysporum tobira* on the surface of the experimental sample is significantly lower than that of the control sample. This indicates that the surface-modified water-based self-polishing antifouling coating provided in Example 1 has an inhibitory effect on the growth and adhesion of *Dysporum tobira*.

[0103] The above description is only a preferred embodiment of the present invention. It should be noted that for those skilled in the art, several improvements and modifications can be made without departing from the principle of the present invention, and these improvements and modifications should also be considered within the scope of protection of the present invention.

Claims

1. A surface-modified and reinforced water-based self-polishing antifouling coating, characterized in that, Includes separately packaged ATRP initiator slurry and sSI-ATRP reaction solution; The raw materials for preparing the ATRP initiator slurry include an aqueous self-polishing emulsion, an aqueous slurry, and a film-forming aid. The mass ratio of the aqueous self-polishing emulsion, aqueous slurry, and film-forming aid is (20~50):(30~60):(5~15); The aqueous self-polishing emulsion comprises the following raw materials in the indicated mass percentages: 0.5-2% acrylic acid, 10-30% acrylate silicone monomers, 20-50% vinyl unsaturated monomers, 2-5% polymerizable ATRP initiator monomers, 0.5-3% emulsifier, 0.1-2% initiator, 0.01-1% sodium bicarbonate, 0.1-1% pH adjuster, 10-20% rosin, and the balance being water; the ATRP initiator monomer is 2-((2-bromo-2-methylpropionyl)oxy)ethyl methacrylate; The components of the aqueous slurry include antifouling agent, pigments and fillers, bentonite, thickener, dispersant, defoamer and water; the solid content of the aqueous slurry is 40%~55%; the antifouling agent is one or more of diuron, copper pyrithione, zinc pyrithione, 4,5-dichloro-N-octyl-3-isothiazolinone, capsaicin, allicin and zineb, and the mass ratio of the antifouling agent to water is (5~10):(20~50); The components of the sSI-ATRP reaction solution include an alkenyl monomer, 2,2-bipyridine, a catalyst, and a solvent; The application method of the surface-modified and enhanced water-based self-polishing antifouling coating includes the following steps: The ATRP initiator slurry was coated onto the substrate surface to obtain a water-based self-polishing and anti-fouling coating. The substrate containing the water-based self-polishing antifouling coating is immersed in the sSI-ATRP reaction solution to carry out the sSI-ATRP reaction, thereby obtaining a surface-modified and enhanced water-based self-polishing antifouling coating.

2. The surface-modified and enhanced water-based self-polishing antifouling coating according to claim 1, characterized in that, The pigments and fillers include one or more of zinc oxide, mica powder, talc powder, barium oxide, and iron oxide red.

3. The surface-modified and enhanced water-based self-polishing antifouling coating according to claim 1, wherein the thickener comprises one or more of methylcellulose, hydroxyethylcellulose, and sodium carboxymethylcellulose.

4. The surface-modified and enhanced waterborne self-polishing antifouling coating according to claim 1, wherein the dispersant comprises one or more of PL-20, fluorinated anionic surfactant, BYK156, and BYK152; The defoamer includes one or more of BYK025, DAPROAP7010, and 810 defoamers.

5. The method for preparing the surface-modified and enhanced waterborne self-polishing antifouling coating according to any one of claims 1 to 4, characterized in that, The preparation method of the ATRP initiator slurry includes the following steps: Acrylic acid, acrylate monomers, vinyl unsaturated monomers, polymerizable ATRP initiator monomers, emulsifiers, initiators, sodium bicarbonate, pH adjusters, rosin, and water are emulsion polymerized to obtain an aqueous self-polishing emulsion. Antifouling agent, pigments and fillers, bentonite, thickener, dispersant, defoamer and water are mixed and ground to obtain water-based slurry; The aqueous self-polishing emulsion, aqueous slurry, and film-forming aid are mixed to obtain an ATRP initiator slurry. The preparation method of the sSI-ATRP reaction solution includes the following steps: mixing alkenyl monomer, 2,2-bipyridine, catalyst and solvent to obtain the sSI-ATRP reaction solution.

6. A method for preparing a surface-modified and enhanced water-based self-polishing antifouling coating, characterized in that, Includes the following steps: An ATRP initiator slurry is coated onto the surface of a substrate to obtain a water-based self-polishing antifouling coating; the ATRP initiator slurry is the ATRP initiator slurry in any one of the surface-modified and enhanced water-based self-polishing antifouling coatings according to any one of claims 1 to 4; The substrate containing the water-based self-polishing antifouling coating is immersed in the sSI-ATRP reaction solution to carry out the sSI-ATRP reaction, thereby obtaining the surface-modified and enhanced water-based self-polishing antifouling coating. The sSI-ATRP reaction solution is the sSI-ATRP reaction solution in the surface-modified and enhanced water-based self-polishing antifouling coating according to any one of claims 1 to 4.

7. The preparation method according to claim 6, characterized in that, The sSI-ATRP reaction was carried out at room temperature for 5-60 minutes.

8. The surface-modified and enhanced waterborne self-polishing antifouling coating prepared by the preparation method according to claim 6 or 7, characterized in that, This includes water-based self-polishing antifouling coatings and polymer brushes applied to the surface of the water-based self-polishing antifouling coating.

9. The surface-modified and enhanced water-based self-polishing and antifouling coating according to claim 8, characterized in that, The thickness of the polymer brush is 5~35μm.

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