A silicone-modified acrylic resin antifouling paint and a method for preparing the same

Abstract

The application discloses an organic silicon modified acrylic resin antifouling paint and a preparation method thereof, and particularly relates to the field of chemical coating. The antifouling paint comprises, in parts by mass, 8-12 parts of adamantane acrylate, 5-8 parts of trifluoroethyl acrylate, 2-3 parts of 2-hydroxyethyl acrylate phosphate, 0.8-1.2 parts of tert-butyl peroxy neopentanoate, 4-6 parts of tridecafluoro octyl trimethoxysilane, 1-2 parts of isophorone diisocyanate, 3-6 parts of fluorosilane modified nano TiO2, 1-2 parts of graphene oxide, 20-30 parts of deionized water, 0.5-1 part of polyether modified polysiloxane defoaming agent, and 0.3-0.5 part of ultraviolet absorber UV-327 which can be additionally added. The preparation method comprises the following steps: S1, preparing isocyanate modified fluorine-containing organic silicon; S2, preparing a terpolymer prepolymer; S3, preparing a modified resin matrix; S4, preparing a fluorosilane modified nano TiO2 / graphene oxide composite filler dispersion liquid; and S5, mixing the resin matrix and the dispersion liquid, and stirring and vacuum desolventizing to obtain the finished product. The product has the characteristics of super-hydrophobicity, high hardness, strong adhesion, long-acting antifouling, aging resistance and environmental protection.

Description

Technical Field

[0001] This invention relates to the field of chemical coatings technology, and more specifically, to an organosilicon-modified acrylic resin antifouling coating and its preparation method. Background Technology

[0002] Antifouling coatings are widely used on the surfaces of substrates such as metals (e.g., aluminum plates) and concrete to resist the adhesion of pollutants (e.g., biofouling, chemical stains) and corrosion from water and air, ensuring the long-term stable use of the substrate. However, existing antifouling coating technologies still have several core shortcomings that make it difficult to meet practical application needs:

[0003] Traditional antifouling coatings often add large amounts of fluorinated flexible monomers to improve hydrophobicity (reducing pollutant adhesion), which leads to a decrease in coating hardness (mostly 1H and below), weak scratch and deformation resistance, and easy loss of antifouling function due to external damage. If rigid monomers are added to improve hardness, the hydrophobic arrangement of fluorinated chains will be disrupted, the surface energy will increase, and the hydrophobicity will be greatly reduced (the water contact angle is mostly below 140°), forming an inherent contradiction between hydrophobicity and hardness.

[0004] Existing fluorinated antifouling coatings often directly add fluorinated silanes (such as tridecafluorooctyltrimethoxysilane). Because the fluorinated chains lack fixed anchoring points, they are prone to migrate into the coating or be lost with the medium during use, resulting in a rapid decline in hydrophobicity (the migration rate of fluorinated chains can reach more than 35% after 100 hours of immersion), an increased water contact angle (more than 18°), and the antifouling effect usually fails within a few months.

[0005] Most traditional antifouling coatings rely solely on hydrophobicity to achieve antifouling, which cannot cope with complex pollution scenarios. They have no ability to degrade already attached chemical pollutants (such as organic stains like Rhodamine B), and their adhesion barrier effect on microorganisms in water (such as Vibrio vulnificus) is poor (the adhesion rate often exceeds 25% in 72 hours). At the same time, the coating is not dense enough and has high water permeability (the water absorption rate in 24 hours is often greater than 3%), which can easily lead to substrate corrosion.

[0006] In outdoor environments, ultraviolet light (290-400nm) can easily damage the C-C bonds, CF bonds, and Si-O bonds in the coating resin matrix, leading to discoloration and cracking of the coating. At the same time, ultraviolet light can induce crystal transformation of nano-photocatalytic fillers, causing them to lose their photocatalytic activity and further shortening the service life of the coating.

[0007] To ensure the fluidity of some antifouling coatings, a large amount of organic solvents need to be added, and the residual solvent content often exceeds 1 wt%, resulting in excessive release of volatile organic compounds (VOCs). If the amount of solvent is reduced, the viscosity of the coating will be abnormal (below 800 mPa·s or above 1200 mPa·s), making it unsuitable for conventional construction methods such as brushing and spraying, resulting in a low finished product qualification rate.

[0008] Therefore, an organosilicon-modified acrylic resin antifouling coating and its preparation method are proposed. Summary of the Invention

[0009] In order to overcome the above-mentioned defects of the prior art, the present invention provides an organosilicon-modified acrylic resin antifouling coating and its preparation method, so as to solve the problems mentioned in the background art.

[0010] To achieve the above objectives, the present invention provides the following technical solution: an organosilicon-modified acrylic resin antifouling coating, comprising the following components in parts by weight:

[0011] 8-12 parts adamantane acrylate, 5-8 parts trifluoroethyl acrylate, 2-3 parts 2-hydroxyethyl acrylate phosphate, 0.8-1.2 parts tert-butyl peroxypentanoate, 4-6 parts tridecafluorooctyltrimethoxysilane, 1-2 parts isophorone diisocyanate, 3-6 parts fluorosilane-modified nano-TiO2, 1-2 parts graphene oxide, 20-30 parts deionized water, 0.5-1 part polyether-modified polysiloxane defoamer;

[0012] The organosilicon-modified acrylic resin antifouling coating has a water contact angle ≥150° and a water contact angle hysteresis ≤10° at 25°.

[0013] The solid content of the organosilicon-modified acrylic resin antifouling coating is 35-40 wt%, and the viscosity at 25°C is 800-1200 mPa·s.

[0014] The rigid cyclic structure of adamantane and the long-chain hydrophobic structure of trifluoroethyl acrylate monomer form a rigid-flexible balance, avoiding the brittleness of pure rigid resin or the poor adhesion of pure fluoropolymer resin. The hydroxyl groups (-OH) of 2-hydroxyethyl acrylate phosphate provide active sites for subsequent cross-linking with isocyanate, while its phosphate groups (-PO4H2) can form coordination bonds with metal and concrete substrates, locking hydrophobicity, rigidity, and adhesion in the resin skeleton. This allows the resin matrix to simultaneously possess high hardness, superhydrophobicity, and grade 0 adhesion, solving the pain points of traditional antifouling coatings where hardness and hydrophobicity cannot be achieved simultaneously, and where hydrophobicity and adhesion are contradictory.

[0015] The -NCO group of isophorone diisocyanate first reacts with the -Si-OH of fluorinated silane to form an intermediate between fluorinated silane and isocyanate; the remaining -NCO of the intermediate then crosslinks with the -OH of the ternary copolymer prepolymer, anchoring the ultra-long fluorine chain (twelfthofluorooctyl) in the resin matrix, preventing the fluorine chain from migrating and being lost. This allows the fluorine chain to form a stable hydrophobic layer on the coating surface. The water contact angle hysteresis ≤10° improves the superhydrophobic stability, and the crosslinking structure enhances the resin's solvent resistance, solving the problems of easy migration of fluorine chains and poor antifouling durability in traditional fluorinated coatings.

[0016] Furthermore, by combining fluorosilane-modified nano-TiO2 with graphene oxide, TiO2 photocatalytically degrades pollutants, while graphene physically blocks water and pollutants. Specifically, fluorosilane modification makes the TiO2 surface hydrophobic, improving its compatibility with the resin matrix, preventing nanoparticle aggregation, and maximizing the photocatalytic contact area. The layered structure of graphene oxide forms a labyrinthine barrier network in the coating, slowing the penetration of water and pollutants into the substrate, while providing support for TiO2 and extending its photocatalytic lifespan. This achieves dual antifouling protection through surface degradation and deep barrier.

[0017] Preferably, it also includes 0.3-0.5 parts of ultraviolet absorber UV-327.

[0018] Specifically, since UV-327 is a benzophenone-based UV absorber, it can absorb 290-400nm UV light through intramolecular hydrogen bond transfer, which is the main outdoor aging light source. It converts UV light energy into harmless heat energy and releases it, thus preventing the C-C bonds, CF bonds, and Si-O bonds of the resin matrix from being damaged by UV light.

[0019] The combination of UV-327 with the resin matrix and composite filler can protect the functional components from aging. This is mainly because UV-327 has a stable molecular structure and good compatibility with fluorine-containing groups, and will not damage the fluorine hydrophobic layer on the coating surface. Secondly, it avoids the transformation of nano-TiO2 crystal form caused by ultraviolet light, and at the same time prevents the oxidation and degradation of graphene oxide sheets, thus extending the functional life of the composite filler and avoiding easy aging and rapid decline in antifouling performance.

[0020] A method for preparing an organosilicon-modified acrylic resin antifouling coating includes the following steps:

[0021] S1. Mix tridecafluorooctyltrimethoxysilane and isophorone diisocyanate at a mass ratio of 4-6:1-2, add 0.1-0.3% of dibutyltin dilaurate catalyst according to the total mass of the two, and stir the reaction at 50-60℃ for 1-2 h to obtain isocyanate modified fluorinated organosilicon.

[0022] S2. By mass, mix 8-12 parts of adamantane acrylate, 5-8 parts of trifluoroethyl acrylate, and 2-3 parts of 2-hydroxyethyl acrylate phosphate evenly, add 0.8-1.2 parts of tert-butyl peroxypentanoate initiator, purge the air in the reaction system with nitrogen, raise the temperature to 85-95℃, and maintain the temperature for prepolymerization for 2-3 hours to obtain the ternary copolymer prepolymer.

[0023] S3. Add the ternary copolymer prepolymer to a reactor equipped with stirring and temperature control, heat to 90-100℃, and add isocyanate-modified fluorinated organosilicon at a rate of 1-2 drops / second. After the addition is completed, continue to keep the temperature for 3-4 hours. During this period, take a sample every 30 minutes to detect the gel rate of the system until the gel rate is ≤0.5%. Stop the heat preservation to obtain the modified resin matrix.

[0024] S4. Take fluorosilane-modified nano-TiO2 and graphene oxide at a mass ratio of 1-3:1, add 20-30 parts of deionized water, and ultrasonically disperse at 300-500W power for 30-60 minutes to obtain a composite filler dispersion. The fluorosilane-modified nano-TiO2 is anatase nano-TiO2 modified with perfluorooctyltriethoxysilane.

[0025] S5. Finally, the modified resin matrix and the composite filler dispersion are mixed at a mass ratio of 8-10:1, and 0.5-1 part of polyether modified polysiloxane defoamer is added. The mixture is stirred at 500-800 rpm for 1-2 hours at 60-70℃. Then, the vacuum degree of the reaction system is adjusted to -0.6 to -0.7 MPa, and the residual solvent is removed by heat treatment for 1-1.5 hours until the residual solvent content is ≤0.1wt%. The mixture is then cooled to room temperature to obtain the organosilicon modified acrylic resin antifouling coating.

[0026] Specifically, in S1, dibutyltin dilaurate acts as an organotin catalyst to catalyze the nucleophilic addition reaction between the -NCO group of isophorone diisocyanate and the -Si-OH group of tridecafluorooctyltrimethoxysilane, generating a modified fluorinated organosilicon containing free -NCO. 50-60℃ is the optimal reaction temperature because the reaction is slow at too low a temperature and easily leads to the self-polymerization of -NCO. Thus, by controlling the reaction with catalyst, the selectivity of the reaction between -NCO and -Si-OH is ensured, and the side reaction of -NCO does not occur. A bifunctional intermediate containing fluorinated chains and crosslinkable -NCO is obtained, which lays the foundation for subsequent crosslinking with the prepolymer and avoids the problems of non-anchoring and easy migration when using fluorinated silanes directly.

[0027] In S2, under nitrogen protection, tert-butyl peroxypentanoate generates free radicals, which initiate free radical copolymerization of adamantane acrylate, trifluoroethyl acrylate, and 2-hydroxyethyl phosphate acrylate. The three monomers are uniformly incorporated into the polymer chain according to their activity ratio, thereby introducing three functional groups—rigidity, hydrophobicity, and adhesion—into the prepolymer in one step, avoiding uneven component composition caused by subsequent stepwise addition. Nitrogen protection prevents the free radicals from being oxidized, ensuring copolymerization efficiency. The prepolymer has a narrow molecular weight distribution (PDI=1.2-1.5) and stable subsequent crosslinking properties.

[0028] In S3, the modified fluorinated organosilicon is uniformly dispersed in the prepolymer by a dropping rate of 1-2 drops / second and stirring at 300-400 rpm, avoiding excessive local -NCO concentration that could lead to explosive gelation. The gel rate is checked every 30 minutes to ensure that it is ≤0.5%, ensuring that the crosslinking reaction proceeds gradually and uniformly. This allows the reaction between NCO and -OH to be a stepwise polymerization, resulting in a three-dimensional network structure formed by the crosslinked resin. The rigid segments of adamantane enhance the network strength, the fluorinated segments accumulate on the network surface to form a hydrophobic layer, and the phosphate groups combine with the substrate inside the network, achieving a three-dimensional synergy of strength, hydrophobicity, and adhesion, and avoiding coating performance fluctuations caused by uneven local crosslinking.

[0029] In S4, 300-500W ultrasonic dispersion breaks up the agglomerates of nano-TiO2 and graphene oxide through cavitation effect; fluorosilane modification grafts hydrophobic groups (-CF3) onto the surface of TiO2, which, after ultrasonic exfoliation, improves the compatibility with the hydrophobic surface of graphene oxide, forming a dispersion structure in which TiO2 particles are interspersed between graphene sheets. This improves the uniformity of composite filler dispersion and avoids photocatalytic dead zones and blockages caused by agglomeration; the dispersion of TiO2 between graphene sheets expands the photocatalytic contact area and enhances the stability of graphene sheets, preventing sheet recombination and improving antifouling durability.

[0030] In S5, the resin matrix and composite filler are thoroughly mixed at 500-800 rpm under a temperature of 60-70℃, ensuring the temperature matches the cloud point of the defoamer and the stirring rate balances dispersibility and avoids bubbles. Vacuum desolventizing at -0.6 to -0.7 MPa lowers the solvent boiling point through negative pressure, achieving gradual solvent removal. Programmed temperature increases further prevent solvent boiling over, allowing the defoamer, i.e., polyether-modified polysiloxane, to exert its optimal defoaming effect at 60-70℃, eliminating bubbles generated during stirring and preventing pinholes in the coating. Vacuum desolventizing to a residue of ≤0.1 wt% results in no VOCs release, meeting environmental requirements while avoiding coating swelling and reduced water resistance caused by solvent residue, ultimately yielding a uniform and dense coating.

[0031] Preferably, in step S1, the purity of tridecafluorooctyltrimethoxysilane is ≥99%, and the NCO value of isophorone diisocyanate is 37.5-38.5%.

[0032] Specifically, limiting the purity of tridecafluorooctyltrimethoxysilane is crucial because impurities (such as short-chain fluorosilanes and alcohols) competitively consume the -NCO groups of isocyanate, resulting in insufficient free -NCO content in the modified fluorinated organosilicon and subsequent inability to fully crosslink with the prepolymer. High purity ensures that each silane molecule can react with -NCO to form a regular structure of fluorine chain and isocyanate. Furthermore, isophorone diisocyanate has an NCO value of 37.5-38.5%, which directly reflects the -NCO group content; below 37.5% indicates insufficient crosslinking sites and a compromised resin network. The coating is porous; if the content exceeds 38.5%, the excess -NCO will react with moisture in the air to form urea bonds, causing the coating to yellow. This range ensures that there is still sufficient -NCO to crosslink with the prepolymer after reacting with silane, and there is no excessive side reaction. In this way, by using high-purity silane and isocyanate with a suitable NCO value, the free -NCO content of the modified fluorinated organosilicon is stabilized at 8-10% by mass fraction, which improves the efficiency of subsequent crosslinking with the prepolymer and makes the fluorine content on the coating surface stable at 18-20%, with water contact angle fluctuation ≤±2°, thus solving the problem of performance instability caused by raw material purity.

[0033] Preferably, in step S2, the mass ratio of adamantane acrylate, trifluoroethyl acrylate, and 2-hydroxyethyl acrylate phosphate is 4:3:1, and the purity of tert-butyl peroxypentanoate is ≥98%.

[0034] Specifically, when the mass ratio of adamantane acrylate, trifluoroethyl acrylate, and 2-hydroxyethyl acrylate is 4:3:1, the glass transition temperature (Tg) of the resin matrix remains stable at 55-60℃, balancing hardness and flexibility. The surface energy is reduced to 18-20 mN / m, achieving a superhydrophobic threshold and adhesion to the substrate ≥5 MPa. This avoids deviations in the ratio, which can lead to coating brittleness due to excessive adamantane, decreased adhesion due to excessive fluorine monomers, and decreased hydrophobicity due to excessive phosphate esters. Furthermore, since impurities can terminate free radical polymerization, leading to a decrease in prepolymer molecular weight and insufficient resin strength after subsequent crosslinking, the purity of the initiator, specifically tert-butyl peroxypentanoate, is limited. High-purity initiators ensure stable free radical concentrations, and the prepolymer molecular weight is controlled within the optimal crosslinking molecular weight range of 2 × 10⁻⁶. 4 -3×10 4 Inside;

[0035] In this way, by combining the monomer ratio with a high-purity initiator, the rigidity, hydrophobicity and adhesion of the prepolymer are optimally balanced. After crosslinking with modified fluorinated organosilicon, the coating has both scratch resistance and maintains grade 0 adhesion to prevent peeling, while the water contact angle is ≥150°.

[0036] Preferably, in step S3, when adding isocyanate-modified fluorinated organosilicon, the stirring rate in the reactor is 300-400 rpm, and the temperature fluctuation range of the heat preservation reaction is ≤±2℃.

[0037] Specifically, speeds below 300 rpm will result in uneven dispersion of the modified fluorinated organosilicon, excessively high local -NCO concentration, and the appearance of gel points; speeds above 400 rpm will introduce too much air, forming bubbles that are difficult to eliminate later; this speed ensures uniform dispersion of the modified silane without obvious bubbles.

[0038] Since the reaction rate of NCO and -OH is temperature-sensitive, the reaction rate doubles for every 5°C increase in temperature. Excessive fluctuations lead to localized differences in reaction rate, resulting in uneven crosslinking density. This causes hard and soft areas to coexist, causing fluctuations in the mechanical properties of the coating. A fluctuation of ±2°C ensures a stable reaction rate and uniform crosslinking density. By combining stirring rate and temperature control, the uniformity of crosslinking density of the modified resin matrix is ​​improved, and the surface smoothness (Ra) of the coating is ≤0.2μm. This avoids brittleness caused by excessively dense crosslinking or poor water resistance caused by excessively sparse crosslinking, ensuring uniform coating performance.

[0039] Preferably, in step S4, the particle size of the fluorosilane-modified nano-TiO2 is 20-50 nm, the thickness of the graphene oxide sheets is 0.8-1.2 nm, and the number of layers is ≤5.

[0040] Specifically, fluorosilane-modified nano-TiO2 with a particle size that is too small (<20nm) is prone to agglomeration, resulting in a decrease in photocatalytic area; if the particle size is too large (>50nm), it will lead to an increase in the surface roughness of the coating (Ra>0.5μm), destroying the superhydrophobicity and causing the water contact angle to decrease to <140°; a particle size of 20-50nm ensures a specific surface area ≥50m². 2 / g, which also controls the coating roughness to the optimal superhydrophobic roughness of 0.1-0.2μm.

[0041] The thickness of the graphene oxide sheets is 0.8-1.2 nm, and the number of layers is ≤5. A thickness >1.2 nm or a number of layers >5 will lead to a decrease in the barrier properties of the sheets, resulting in an increase in water permeability. This parameter ensures that the graphene sheets are single-atom-layer, few-layer structures, forming a dense barrier network and reducing water permeability. By matching the filler particle size with the graphene structure, the composite filler in the coating forms a dual-layer functional structure of a nano-TiO2 photocatalytic layer and a graphene barrier layer: TiO2 degrades surface pollutants and prevents pollutant adhesion, while graphene blocks water / pollutant penetration and prevents substrate corrosion, thereby improving the antifouling life.

[0042] Preferably, in step S5, the turbidity point of the polyether-modified polysiloxane defoamer is 65-70℃, and the amount added is 0.5-0.8% of the total mass of the modified resin matrix and the composite filler dispersion.

[0043] Specifically, the cloud point is the temperature at which the defoamer transitions from a dissolved state to a dispersed state, which is 65-70℃. This matches the stirring temperature of S5, which is 60-70℃. At this temperature, the defoamer forms tiny droplets, effectively eliminating bubbles generated during stirring. This avoids the cloud point deviation, which results in a dissolved state with no defoaming effect below 60℃ and agglomeration and decreased defoaming efficiency above 75℃. By limiting the amount of polyether-modified polysiloxane defoamer added, thorough defoaming without surface defects can be ensured. The cloud point and dosage of the defoamer are limited, eliminating bubbles in real time during stirring without affecting the compatibility of the resin and filler. The defoamer is a polyether-modified polysiloxane, which has good compatibility with fluorinated resins and can reduce the surface defect rate of the coating. The defoamer does not affect the fluorine chain arrangement, so the water contact angle does not decrease, thus resolving the contradiction between defoaming and coating performance.

[0044] Preferably, in step S5, when removing residual solvent, a programmed temperature rise is adopted: first, the temperature is raised to 65°C at a rate of 2°C / min and held for 0.5h, then the temperature is raised to 70°C at a rate of 1°C / min and held for 1h.

[0045] Specifically, first slowly heat to 65°C: low-boiling-point residual solvents evaporate first, avoiding rapid heating that could cause solvent to boil violently and carry out resin particles to form pores;

[0046] Reheat to 70℃: remove residual high-boiling-point solvents, and keep warm for 1 hour to ensure complete solvent removal;

[0047] By employing programmed temperature rise and vacuum desolventizing, the residual solvent content is kept stable at ≤0.1wt%, and the resin matrix does not undergo thermal aging. This improves the density of the coating and solves the problems of environmental non-compliance caused by residual solvent and resin performance degradation caused by high-temperature desolventizing.

[0048] Preferably, in step S5, 0.3-0.5 parts of ultraviolet absorber are added simultaneously during the addition of defoamer.

[0049] Specifically, when added simultaneously with the defoamer during the stirring process, the ultraviolet absorber (UV-327) can be evenly dispersed in the coating. If added separately later, the high viscosity of the coating (800-1200 mPa·s) can easily lead to uneven dispersion, resulting in local concentrations that are too high or too low. Furthermore, since UV-327 is oil-soluble, it has good compatibility with the resin matrix and defoamer, does not stratify, and will not affect the fluorine chain arrangement and filler dispersion.

[0050] In this way, the simultaneous addition ensures that UV-327 is evenly distributed in the coating, the UV absorption per unit volume of coating is stable, the protective effect on the resin matrix and composite filler is uniform, and uneven aging caused by insufficient local UV absorption is avoided, thereby extending the antifouling life.

[0051] The present invention provides an organosilicon-modified acrylic resin antifouling coating and its preparation method, which have the following beneficial effects:

[0052] The rigid cyclic structure of adamantane acrylate and the long-chain hydrophobic structure of trifluoroethyl acrylate form a rigid-flexible balance. Combined with the dual effect of 2-hydroxyethyl acrylate phosphate, the coating achieves a stable water contact angle of ≥150° at 25°C, a pencil hardness of ≥2H, and a cross-cut adhesion of 0 to aluminum plates and concrete substrates. This allows the coating to resist daily external damage while maintaining superhydrophobicity and antifouling properties.

[0053] To achieve long-term stability of superhydrophobic properties and prevent fluorine chain migration, isophorone diisocyanate is used to pre-modify tridecafluorooctyltrimethoxysilane. Through crosslinking of the -NCO group with the -OH group of the ternary copolymer prepolymer, the ultra-long fluorine chain (tridecafluorooctyl) is anchored in the three-dimensional network of the resin. The 100-hour immersion test shows that the fluorine chain migration rate is only 5%, and the water contact angle hysteresis is ≤10°, ensuring that the superhydrophobic properties do not degrade during long-term use and improving the durability of antifouling.

[0054] A dual antifouling system combining photocatalytic degradation and physical barrier is constructed. Fluorosilane-modified nano-TiO2 and graphene oxide form a synergistic effect: TiO2 can efficiently degrade chemical pollutants attached to the surface under ultraviolet light irradiation, while the sheet structure of graphene oxide forms a labyrinthine barrier network in the coating, slowing down the penetration of water and microorganisms into the substrate.

[0055] Significantly improves outdoor aging resistance and extends service life. By adding 0.3-0.5 parts of UV absorber UV-327 and defoamer simultaneously during the coating preparation process, it can effectively absorb outdoor ultraviolet light and avoid resin bond breakage and functional component failure. Detailed Implementation

[0056] Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0057] Example 1

[0058] The silicone-modified acrylic resin antifouling coating provided in Example 1 comprises the following components by weight:

[0059] 10 parts adamantane acrylate, 6.5 parts trifluoroethyl acrylate, 2.5 parts 2-hydroxyethyl acrylate phosphate, 1 part tert-butyl peroxypentanoate, 5 parts tridecafluorooctyltrimethoxysilane, 1.5 parts isophorone diisocyanate, 0.0098 parts dibutyltin dilaurate, 4.5 parts fluorosilane-modified nano-TiO2, 1.5 parts graphene oxide, 25 parts deionized water, and 0.75 parts polyether-modified polysiloxane defoamer.

[0060] A method for preparing an organosilicon-modified acrylic resin antifouling coating includes the following steps:

[0061] S1. Mix tridecafluorooctyltrimethoxysilane with isophorone diisocyanate, add dibutyltin dilaurate, and stir at 55°C for 1.5 h to obtain a pale yellow transparent liquid isocyanate-modified fluorinated organosilicon.

[0062] S2. Mix the resin monomers and initiator, purge with nitrogen three times for 10 minutes each time, heat to 90°C and hold for 2.5 hours to prepolymerize, and obtain a viscous transparent ternary copolymer prepolymer.

[0063] S3. Add the ternary copolymer prepolymer to the reactor, heat to 95℃, adjust the stirring speed to 350rpm, add the product of S1 dropwise at a rate of 1.5 drops / second, keep warm for 3.5h after the addition is complete, take a sample every 30min to measure the gelation rate, stop the reaction, and obtain the modified resin matrix.

[0064] S4. Mix fluorosilane-modified nano-TiO2 and graphene oxide, add deionized water, and ultrasonically disperse at 400W power for 45 minutes to obtain a uniform composite filler dispersion.

[0065] S5. Mix the modified resin matrix and composite filler dispersion, add defoamer, stir at 65℃ and 650rpm for 1.5h, adjust the vacuum degree to -0.65MPa, program the temperature to desolvate, raise the temperature to 65℃ at 2℃ / min and keep it at 0.5h, then raise the temperature to 70℃ at 1℃ / min and keep it at 1h, cool to room temperature to obtain a milky white coating, namely organosilicon modified acrylic resin antifouling coating.

[0066] Example 2

[0067] This embodiment 2 provides an organosilicon-modified acrylic resin antifouling coating, which comprises the following components by weight:

[0068] 12 parts adamantane acrylate, 8 parts trifluoroethyl acrylate, 3 parts 2-hydroxyethyl acrylate phosphate, 1.2 parts tert-butyl peroxypentanoate, 6 parts tridecafluorooctyltrimethoxysilane, 2 parts isophorone diisocyanate, 0.024 parts dibutyltin dilaurate, 6 parts fluorosilane-modified nano-TiO2, 2 parts graphene oxide, 30 parts deionized water, and 1 part polyether-modified polysiloxane defoamer.

[0069] A method for preparing an organosilicon-modified acrylic resin antifouling coating includes the following steps:

[0070] S1. Mix tridecylfluorooctyltrimethoxysilane with isophorone diisocyanate, add dibutyltin dilaurate, and stir at 60°C for 2 hours to obtain a pale yellow transparent liquid isocyanate-modified fluorinated organosilicon.

[0071] S2. Mix the resin monomers and initiator, purge with nitrogen three times for 10 minutes each time, heat to 95°C and hold for 3 hours to prepolymerize, and obtain a viscous transparent ternary copolymer prepolymer.

[0072] S3. Add the ternary copolymer prepolymer to the reactor, heat to 100℃, adjust the stirring speed to 400rpm, add the product of S1 drop by drop at a rate of 2 drops / second, keep warm for 4h after the addition is complete, take a sample every 30min to measure the gelation rate, stop the reaction, and obtain the modified resin matrix.

[0073] S4. Mix fluorosilane-modified nano-TiO2 and graphene oxide, add deionized water, and ultrasonically disperse at 500W power for 60 minutes to obtain a uniform composite filler dispersion.

[0074] S5. Mix the modified resin matrix and composite filler dispersion, add defoamer, stir at 75℃ and 800rpm for 2h, adjust the vacuum degree to -0.7MPa, program the temperature to desolvent, raise the temperature to 65℃ at 2℃ / min and keep it at 0.5h, then raise the temperature to 70℃ at 1℃ / min and keep it at 1h, cool to room temperature to obtain milky white coating, namely organosilicon modified acrylic resin antifouling coating.

[0075] Example 3

[0076] The silicone-modified acrylic resin antifouling coating provided in Example 3 comprises the following components by weight:

[0077] 8 parts adamantane acrylate, 5 parts trifluoroethyl acrylate, 2 parts 2-hydroxyethyl acrylate phosphate, 0.8 parts tert-butyl peroxypentanoate, 4 parts tridecafluorooctyltrimethoxysilane, 1 part isophorone diisocyanate, 0.005 parts dibutyltin dilaurate, 3 parts fluorosilane-modified nano-TiO2, 1.5 parts graphene oxide, 20 parts deionized water, and 0.5 parts polyether-modified polysiloxane defoamer.

[0078] A method for preparing an organosilicon-modified acrylic resin antifouling coating includes the following steps:

[0079] S1. Mix tridecylfluorooctyltrimethoxysilane with isophorone diisocyanate, add dibutyltin dilaurate, and stir at 50°C for 1 hour to obtain a pale yellow transparent liquid isocyanate-modified fluorinated organosilicon.

[0080] S2. Mix the resin monomers and initiator, purge with nitrogen three times for 10 minutes each time, heat to 85°C and hold for 2 hours to prepolymerize, and obtain a viscous transparent ternary copolymer prepolymer.

[0081] S3. Add the ternary copolymer prepolymer to the reactor, heat to 90℃, adjust the stirring speed to 300rpm, add the product of S1 drop by drop at a rate of 1 drop / second, keep warm for 3h after the addition is complete, take a sample every 30min to measure the gelation rate, stop the reaction, and obtain the modified resin matrix.

[0082] S4. Mix fluorosilane-modified nano-TiO2 and graphene oxide, add deionized water, and ultrasonically disperse at 300W power for 30 minutes to obtain a uniform composite filler dispersion.

[0083] S5. Mix the modified resin matrix and composite filler dispersion, add defoamer, stir at 60℃ and 500rpm for 1h, adjust the vacuum degree to -0.6MPa, program the temperature to desolvent, raise the temperature to 65℃ at 2℃ / min and keep it at 0.5h, then raise the temperature to 70℃ at 1℃ / min and keep it at 1h, cool to room temperature to obtain a milky white coating, namely the organosilicon modified acrylic resin antifouling coating.

[0084] Example 4

[0085] The silicone-modified acrylic resin antifouling coating provided in Example 4 differs from the components in Example 1 in that 0.4 parts of ultraviolet absorber UV-327 are added.

[0086] The preparation method of the organosilicon-modified acrylic resin antifouling coating provided in Example 4 differs from that in Example 1 in that UV absorber UV-327 is added simultaneously with the defoamer in step S5.

[0087] Comparative Example 1

[0088] The silicone-modified acrylic resin antifouling coating provided in Comparative Example 1 differs from that in Example 1 in that 10.0 parts by mass of methyl methacrylate (a common flexible monomer) are used instead of adamantane acrylate, and the preparation method is the same as that in Example 1.

[0089] Comparative Example 2

[0090] The organosilicon-modified acrylic resin antifouling coating provided in Comparative Example 2 differs from the components in Example 1 in that 5.0 parts of tridecafluorooctyltrimethoxysilane (which does not react with isophorone diisocyanate) are directly added, and isophorone diisocyanate and dibutyltin dilaurate are not added. Otherwise, it is the same as in Example 1.

[0091] The preparation method of the organosilicon-modified acrylic resin antifouling coating provided in Comparative Example 2 differs from that in Example 1 in that step S1 is omitted, and tridecafluorooctyltrimethoxysilane is directly added to the prepolymer in S3. Otherwise, it is the same as in Example 1.

[0092] Comparative Example 3

[0093] The silicone-modified acrylic resin antifouling coating provided in Comparative Example 3 differs from the components in Example 1 in that it does not contain fluorosilane-modified nano-TiO2 and graphene oxide, and the amount of deionized water is reduced to 15.0 parts (to maintain the total amount of solvent). Otherwise, it is the same as in Example 1.

[0094] The preparation method of the silicone-modified acrylic resin antifouling coating provided in Comparative Example 3 differs from that in Example 1 in that step S4 is omitted, and step S5 involves directly mixing the modified resin matrix with deionized water; otherwise, the process is the same as in Example 1.

[0095] Comparative Example 4

[0096] The silicone-modified acrylic resin antifouling coating provided in Comparative Example 4 has the same components as those in Example 1 by mass parts.

[0097] The preparation method of the organosilicon-modified acrylic resin antifouling coating provided in Comparative Example 4 differs from that in Example 1 in that, in step S3, the ternary copolymer prepolymer is added to the reactor, heated to 95°C, the stirring speed is adjusted to 350 rpm, and the product of S1 is added dropwise at a rate of 3 drops / second. After the addition is complete, the temperature is maintained for 3.5 hours, and samples are taken every 30 minutes to measure the gelation rate. The reaction is then stopped to obtain the modified resin matrix. The rest is the same as in Example 1.

[0098] Comparative Example 5

[0099] The silicone-modified acrylic resin antifouling coating provided in Comparative Example 5 differs from the components in Example 1 in that 4.5 parts of unmodified anatase nano-TiO2 (35nm particle size, without fluorinated silane modification) are used instead of fluorinated silane-modified nano-TiO2, while the rest is the same as in Example 1.

[0100] The preparation method of the organosilicon-modified acrylic resin antifouling coating provided in Comparative Example 5 differs from that in Example 1 in that the ultrasonic treatment at 400W for 45 minutes is performed in step S4, while the rest is the same as in Example 1.

[0101] Experimental Test

[0102] The water contact angle and water contact angle hysteresis test at 25℃ include the following test methods:

[0103] 1. Sample preparation: The coating was evenly sprayed onto a 100mm×100mm×2mm aluminum plate, cured at room temperature for 72 hours, and the surface was polished until Ra≤0.2μm;

[0104] 2. Instrument: Contact angle measuring instrument;

[0105] 3. Procedure: At 25℃ and 50% relative humidity, place 5μL of deionized water on the sample surface, select 5 different measurement points (avoiding the edges), record the contact angle values, and take the average value;

[0106] Meanwhile, using the tilting method of the contact angle measuring instrument, the sample stage is slowly tilted (tilt rate 1° / s), and the contact angle (forward angle - backward angle) when the water droplet begins to roll is recorded. The difference is the contact angle hysteresis, and the average value of 3 tests is taken.

[0107] Pencil hardness testing methods include:

[0108] 1. Sample: Sprayed onto an aluminum plate, cured for 72 hours, thickness 50±5μm;

[0109] 2. Instrument: Pencil hardness tester;

[0110] 3. Procedure: Select a 2H or 3H pencil (sharpen to expose 3mm of lead and grind it smooth), apply a load of 750g, and draw 5 10mm long lines at a 45° angle. Observe whether there are any exposed lines. If there are no exposed lines, it is the hardness grade.

[0111] Cross-cut adhesion test (aluminum plate / concrete), test methods include:

[0112] 1. Samples: Aluminum plates were sprayed with a thickness of 50±5μm (cured for 72h); concrete test blocks (100mm×100mm×50mm) were ground and then sprayed, cured for 72h.

[0113] 2. Instruments: Cross-cut cross-cut tool (1mm x 1mm grid), 3M 600 tape;

[0114] 3. Procedure: Use a cross-cutting tool to cut a 10×10 grid (deep into the substrate), firmly adhere it with tape for 30 seconds, then quickly peel it off at a 45° angle. Observe the area of ​​coating peeling off within the grid. Grade 0 indicates no peeling.

[0115] The photocatalytic degradation rate of Rhodamine B was tested using the following methods:

[0116] 1. Sample: Apply the coating to a glass slide (50mm×50mm×1mm), and after curing, cut it into 1mm×1mm particles (take 0.5g).

[0117] 2. Solution preparation: Prepare 50 mL of 10 mg / L Rhodamine B aqueous solution and add the sample particles;

[0118] 3. Irradiation: Place under a UV lamp (365nm, 100W, 10cm away from the solution) for 4 hours, and take a 5mL sample every 1 hour;

[0119] 4. Detection: Measure the absorbance at 554 nm using a UV spectrophotometer, and calculate the degradation rate as follows: Degradation rate = (initial absorbance - 4h absorbance) / initial absorbance × 100%.

[0120] Marine Vibrio attachment rate test, the test methods include:

[0121] 1. Sample: Sprayed onto a 30mm×30mm aluminum plate, cured for 72 hours, and then sterilized;

[0122] 2. Bacterial solution: Prepare a Vibrio alginolyticus concentration of 10. 6 Artificial seawater bacterial solution with CFU / mL;

[0123] 3. Immersion: Immerse the sample in 50 mL of bacterial solution and let it stand at 25°C for 72 hours;

[0124] 4. Counting: Take out the sample, rinse the surface with sterile physiological saline to wash off the attached bacteria, and count the colonies using the plate count method. The attachment rate is calculated as follows: attachment rate = (number of attached bacteria in the sample / number of attached bacteria in the blank control group) × 100% (the blank control group is an uncoated aluminum plate).

[0125] Solid content test at 25℃, the test method includes:

[0126] 1. Sample: Weigh 2.000g (accurate to 0.001g) of the paint sample into a pre-weighed aluminum dish;

[0127] 2. Drying: Place in a 105℃ forced-air drying oven and dry for 4 hours. After removing, place in a desiccator to cool to room temperature and weigh.

[0128] 3. Calculation: Solid content = (mass after drying / initial sample mass) × 100%, take the average of two parallel experiments.

[0129] Viscosity test at 25℃, the test method includes:

[0130] 1. Sample: Place the coating in a 25℃ constant temperature water bath for 30 minutes;

[0131] 2. Instrument: Rotational viscometer, using a #4 rotor;

[0132] 3. Operation: Adjust the speed to 60 rpm, wait for the pointer to stabilize, and read the value. Take the average of 3 tests.

[0133] The coating samples prepared in Examples 1-4 and Comparative Examples 1-5 were tested respectively, and the test results are shown in Table 1.

[0134] Table 1: Test Results of Examples 1-4 and Comparative Examples 1-5

[0135] Group Contact angle at 25℃ (°) Water contact angle hysteresis Pencil hardness 100-grid adhesion Rhodamine B degradation rate (%) Marine Vibrio attachment rate (%) Solid content (wt%) Viscosity (Pa·s) Example 1 156 8° 2H Level 0 94 3.2 37.5 1050 Example 2 162 7° 3H Level 0 97 2.1 39.2 1180 Example 3 151 9° 2H Level 0 91 4.8 35.8 820 Example 4 (Aging) 143 - 2H Level 0 82 - - - Comparative Example 1 148 - 1H Level 0 92 7.5 37.2 1030 Comparative Example 2 135 18° 2H Level 0 90 12.3 37.0 1010 Comparative Example 3 152 - 2H Level 0 30 25.7 36.8 980 Comparative Example 4 140 - 2H Level 1 88 6.8 37.3 1040 Comparative Example 5 142 - 2H Level 0 65 8.5 37.4 1020

[0136] Meanwhile, samples from Example 1 and Comparative Example 2 were soaked for 100 hours. After soaking, the fluorine chain migration rate in Comparative Example 2 was 35%, while that in Example 1 was 5%. This shows that the absence of isophorone diisocyanate and dibutyltin dilaurate can easily cause fluorine chain migration.

[0137] The water absorption rate of the samples from Comparative Example 3 and Example 1 was tested. After 24 hours of water absorption testing, the water absorption rate of the sample from Comparative Example 3 was 3.2%, while the water absorption rate of Example 1 was only 0.8%. This shows that the absence of fluorosilane-modified nano-TiO2 and graphene oxide leads to an increase in the water absorption rate of the coating.

[0138] The samples of Comparative Example 4 and Example 1 were coated with the coatings, and their surfaces were observed. It was found that the surface of the coating of Comparative Example 4 had pits with a diameter of 0.5-1 mm, while the surface of the coating of Example 1 was smooth. It can be seen that changing the drop rate can affect the final gel rate, thereby affecting the surface smoothness of the coating.

[0139] The above description is merely a preferred embodiment of the present invention and is not intended to limit the present invention. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of the present invention should be included within the protection scope of the present invention.

Claims

1. An organosilicon-modified acrylic resin antifouling paint, characterized by, The following components are included by mass fraction: 8-12 parts of adamantane acrylate, 5-8 parts of trifluoroethyl acrylate, 2-3 parts of 2-hydroxyethyl acrylate phosphate, 0.8-1.2 parts of tert-butyl peroxy pivalate, 4-6 parts of tridecafluorooctyl trimethoxysilane, 1-2 parts of isophorone diisocyanate, 3-6 parts of fluorosilane modified nano-TiO2, 1-2 parts of graphene oxide, 20-30 parts of deionized water, 0.5-1 part of polyether modified polysiloxane defoaming agent; The water contact angle of the organic silicon modified acrylic resin antifouling paint at 25°C is ≥150°, and the water contact angle hysteresis is ≤10°; The solid content of the organic silicon modified acrylic resin antifouling paint is 35-40wt%, and the viscosity at 25°C is 800-1200mPa・s; The modified resin matrix of the organic silicon modified acrylic resin antifouling paint is prepared by the following steps: First, mix tridecafluorooctyl trimethoxysilane and isophorone diisocyanate at a mass ratio of 4-6:1-2, add 0.1-0.3% of dibutyltin dilaurate catalyst based on the total mass of the two, stir and react at 50-60°C for 1-2h to obtain isocyanate modified fluorine-containing silicone; Then, mix adamantane acrylate, trifluoroethyl acrylate, and 2-hydroxyethyl acrylate phosphate uniformly, add tert-butyl peroxy pivalate initiator, replace the air in the reaction system with nitrogen, heat to 85-95°C, and pre-polymerize for 2-3h to obtain a terpolymer pre-polymer; Finally, add the terpolymer pre-polymer to a reaction kettle with stirring and temperature control, heat to 90-100°C, and add the isocyanate modified fluorine-containing silicone at a rate of 1-2 drops per second. After the addition is complete, continue to heat for 3-4h, during which the gel rate of the system is detected every 30min until the gel rate is ≤0.5%, then stop heating to obtain the modified resin matrix.

2. The silicone-modified acrylic resin antifouling paint according to claim 1, characterized by, Also includes 0.3-0.5 parts of ultraviolet absorber UV-327.

3. A method of preparing a silicone-modified acrylic resin antifouling coating according to any one of claims 1-2, characterized in that, The following steps are included: S1, mix tridecafluorooctyl trimethoxysilane and isophorone diisocyanate at a mass ratio of 4-6:1-2, add 0.1-0.3% of dibutyltin dilaurate catalyst based on the total mass of the two, stir and react at 50-60°C for 1-2h to obtain isocyanate modified fluorine-containing silicone; S2, mix 8-12 parts of adamantane acrylate, 5-8 parts of trifluoroethyl acrylate, and 2-3 parts of 2-hydroxyethyl acrylate phosphate by mass fraction, add 0.8-1.2 parts of tert-butyl peroxy pivalate initiator, replace the air in the reaction system with nitrogen, heat to 85-95°C, and pre-polymerize for 2-3h to obtain a terpolymer pre-polymer; S3, add the terpolymer pre-polymer to a reaction kettle with stirring and temperature control, heat to 90-100°C, and add the isocyanate modified fluorine-containing silicone at a rate of 1-2 drops per second. After the addition is complete, continue to heat for 3-4h, during which the gel rate of the system is detected every 30min until the gel rate is ≤0.5%, then stop heating to obtain the modified resin matrix; S4, take fluorosilane modified nano-TiO2 and graphene oxide in a mass ratio of 1-3:1, add 20-30 parts of deionized water, and ultrasonically disperse for 30-60 min under a power of 300-500 W to obtain a composite filler dispersion liquid, wherein the fluorosilane modified nano-TiO2 is anatase type nano-TiO2 modified by perfluorooctyltriethoxysilane; S5, finally mix the modified resin matrix and the composite filler dispersion liquid in a mass ratio of 8-10:1, add 0.5-1 parts of polyether modified polysiloxane defoaming agent, stir at a speed of 500-800 rpm at 60-70℃ for 1-2 h, then adjust the vacuum degree of the reaction system to-0.6 to-0.7 MPa, and heat to remove residual solvents for 1-1.5 h until the residual solvent content is ≤0.1 wt%, and then cool to room temperature to obtain a silicone modified acrylic resin antifouling coating.

4. The method for preparing a silicone-modified acrylic resin antifouling paint according to claim 3, characterized by, In step S1, the purity of tridecafluorooctyltrimethoxysilane is ≥99%, and the NCO value of isophorone diisocyanate is 37.5-38.5%.

5. The method for preparing an organosilicon-modified acrylic resin antifouling coating according to claim 3, characterized in that, In step S2, the mass ratio of adamantyl acrylate, trifluoroethyl acrylate, and 2-hydroxyethyl acrylate phosphate is 4:3:1, and the purity of tert-butyl peroxypivalate is ≥98%.

6. The method for preparing an organosilicon-modified acrylic resin antifouling coating according to claim 3, characterized in that, In step S3, when the isocyanate modified fluorine-containing organosilicon is added dropwise, the stirring speed in the reaction kettle is 300-400 rpm, and the temperature fluctuation range during heat preservation is ≤±2℃.

7. The method for preparing an organosilicon-modified acrylic resin antifouling coating according to claim 3, characterized in that, In step S4, the particle size of the fluorosilane modified nano-TiO2 is 20-50 nm, and the sheet thickness of the graphene oxide is 0.8-1.2 nm with ≤5 layers.

8. The method for preparing an organosilicon-modified acrylic resin antifouling coating according to claim 3, characterized in that, In step S5, the cloud point of the polyether modified polysiloxane defoaming agent is 65-70℃, and the addition amount is 0.5-0.8% of the total mass of the modified resin matrix and the composite filler dispersion liquid.

9. The method for preparing an organosilicon-modified acrylic resin antifouling coating according to claim 3, characterized in that, In step S5, when removing the residual solvents, a programmed temperature rise is used: first, raise the temperature to 65℃ at a rate of 2℃ / min, and then raise the temperature to 70℃ at a rate of 1℃ / min.

10. The method for preparing an organosilicon-modified acrylic resin antifouling coating according to claim 3, characterized in that, In step S5, during the addition of the defoaming agent, 0.3-0.5 parts of an ultraviolet absorber is added simultaneously.