Benzoxazine marine anti-corrosion and anti-fouling paint as well as preparation method and application thereof

Abstract

The invention relates to benzoxazine marine anti-corrosion and anti-fouling paint and a preparation method and application thereof. The preparation method comprises the following steps: mixing paraformaldehyde, 2-aminobenzothiazole and eugenol in a first organic solvent for reaction, cooling and filtering to obtain an intermediate; adding sulfydryl siloxane into the intermediate, and carrying out addition reaction, filtration and solvent removal to obtain benzoxazine resin containing siloxane groups; dissolving benzoxazine resin in a second organic solvent, dropwise adding a hydrophilic high-molecular polymer solution, and stirring for reaction to obtain a composite component; and mixing the composite component with an organosilicon heat-resistant paint, polycaprolactone and an auxiliary agent for reaction to obtain the benzoxazine marine anticorrosive antifouling paint. The hydrophobic benzoxazine resin and the hydrophilic high-molecular polymer are compounded to form the amphiphilic coating, then the amphiphilic coating and the high-cohesiveness polycaprolactone are subjected to covalent cross-linking, and the obtained coating is good in mechanical performance and corrosion resistance and capable of effectively inhibiting microbial adhesion, reducing biofilm formation and achieving the synergistic antifouling effect.

Description

Technical Field

[0001] The present invention relates to the field of antifouling and anticorrosion coatings, and in particular to a benzoxazine marine anticorrosion and antifouling coating, a preparation method thereof, and applications thereof. Background Art

[0002] Marine biofouling refers to the undesirable attachment of marine microorganisms, plants, and animals to ship hulls and subsea equipment, resulting in surface degradation, increased navigation resistance, a sharp increase in fuel consumption, and excessive maintenance costs. Currently, the most effective and convenient way to prevent marine biofouling is to apply one or more layers of coating to the surface of underwater facilities, inhibiting the growth of adherent organisms by controlling the rate at which the coating releases toxic molecules. In this context, bio-based multifunctional coatings derived from natural resources are sustainable and biodegradable, reducing environmental toxicity. They are designed to integrate antifouling, anticorrosion, and other protective properties into a single system, thereby improving overall efficiency.

[0003] Traditional marine bio-based multifunctional coatings can be divided into hydrophobic coatings, hydrophilic coatings, and amphiphilic coatings. The antifouling and anticorrosion mechanism of amphiphilic coatings is that the hydrophilic segments in the amphiphilic coating absorb water in the seawater environment to form a dense hydration layer, which inhibits protein adsorption and microbial adhesion by increasing the free volume and weakening the interfacial bonding between the biofilm and the substrate. Hydrophobic segments (such as polydimethylsiloxane) reduce the strength of biological adhesion through their low surface energy properties, simulating the "lotus effect." However, most coatings themselves do not have anti-corrosion properties. When steel is exposed to the coupled erosion and corrosion of seawater for a long time, its surface will undergo complex physical, chemical, and biological processes, ultimately leading to significant corrosion of the material. At the same time, hydrophobic coatings, such as hydrophobic silicone coatings, often suffer from poor adhesion to the substrate. Summary of the Invention

[0004] The purpose of the present invention is to overcome the above technical deficiencies, provide a benzoxazine marine anticorrosion and antifouling coating and its preparation method and application, and solve the technical problems of poor anticorrosion effect and poor coating adhesion of most marine antifouling coatings in the prior art.

[0005] In order to achieve the above technical objectives, the technical solution provided by the present invention is: In a first aspect, the present invention provides a method for preparing a benzoxazine-based marine anticorrosion and antifouling coating, comprising the following steps: S1, mixing and reacting paraformaldehyde, 2-aminobenzothiazole, and eugenol in a first organic solvent, and cooling and filtering to obtain an intermediate; S2, adding mercaptosiloxane to the intermediate, and subjecting the mixture to an addition reaction, filtering, and solvent removal to obtain a benzoxazine resin containing a siloxane group; S3, dissolving the benzoxazine resin in a second organic solvent, and then dropwise adding a hydrophilic polymer solution, stirring and reacting to obtain a composite component; S4, mixing and reacting the composite component with an organosilicon heat-resistant paint, polycaprolactone, and an additive to obtain a benzoxazine-based marine anticorrosion and antifouling coating.

[0006] In a second aspect, the present invention provides a benzoxazine marine anticorrosion and antifouling coating prepared by the above preparation method.

[0007] In a third aspect, the present invention provides a benzoxazine marine anticorrosion and antifouling coating, which is formed by curing the above-mentioned benzoxazine marine anticorrosion and antifouling coating.

[0008] Compared with the prior art, the present invention has the following beneficial effects: This invention uses paraformaldehyde, 2-aminobenzothiazole, and eugenol for cross-linking to generate a benzothiazolylbenzoxazine resin. This resin is then silicon-modified with mercaptosiloxane to form a hydrophobic benzoxazine resin containing siloxane groups. The siloxane-containing benzoxazine resin has low surface energy and can form a dense barrier, significantly reducing the adhesion of marine organisms and effectively blocking corrosive ions, achieving corrosion resistance comparable to that of silicon-based synthetic resins. The hydrophobic benzoxazine resin is then composited with a hydrophilic polymer to form an amphiphilic coating. The amphiphilic structure creates a dynamic surface: the hydrophobic domains inhibit microbial adhesion, while the hydrophilic segments reduce biofilm formation through a hydration layer, achieving an inhibition rate of >95% against organisms such as algae and barnacles. Covalent cross-linking with highly adhesive polycaprolactone enhances the coating's adhesion (≥5 MPa) and flexibility. The resulting coating exhibits excellent mechanical properties and corrosion resistance, effectively inhibiting microbial adhesion and reducing biofilm formation, achieving a synergistic antifouling effect. BRIEF DESCRIPTION OF THE DRAWINGS

[0009] Figure 1 are photos of bacterial colonies on plates with different coatings of the present invention; Figure 2 are photos of different coatings of the present invention co-cultured with Phaeodactylum tricornutum for 0 and 7 days; Figure 3 These are photos of different coatings of the present invention before and after a 168-h salt spray test; Figure 4 It is the ion release rate of different coatings of the present invention in artificial seawater at room temperature. DETAILED DESCRIPTION

[0010] In order to make the purpose, technical solutions and advantages of the present invention more clearly understood, the present invention will be further described in detail below with reference to the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are only used to explain the present invention and are not intended to limit the present invention.

[0011] In traditional marine bio-based multifunctional coatings, amphiphilic coatings absorb water through their hydrophilic segments to form a dense hydration layer. This increases free volume, weakening the interfacial bonding between the biofilm and the substrate, thereby inhibiting protein adsorption and microbial adhesion. Hydrophobic segments (such as polydimethylsiloxane) reduce bioadhesion strength through their low surface energy, mimicking the "lotus effect." However, most coatings lack inherent corrosion resistance. Long-term exposure to the coupled erosion and corrosion of seawater causes steel surfaces to undergo complex physicochemical and biological processes, ultimately leading to significant corrosion. Furthermore, hydrophobic coatings, such as hydrophobic silicone coatings, often suffer from poor adhesion and mechanical properties.

[0012] For the development of new bio-based multifunctional coatings, polybenzoxazine resins, as a new type of high-performance thermosetting resin, have good mechanical properties and excellent chemical resistance. In theory, incorporating benzothiazole derivatives into the resin can further enhance the protection against metal degradation and the killing effect on microorganisms. However, in response to the problem of marine corrosion, there is currently no literature that introduces corrosion inhibitor benzothiazole derivatives into the resin system to enhance its anti-corrosion efficacy. Moreover, resins with only a single bactericidal effect cannot isolate the attachment of dead bacteria and proteins produced by various microorganisms. Once the coating surface is covered by them, the coating will fail. Therefore, in addition to having bactericidal properties, multifunctional coatings must also resist the adhesion of various biological fouling.

[0013] Based on this, the present invention is proposed.

[0014] Abbreviations PCL: polycaprolactone; PEG: polyethylene glycol; PFA: paraformaldehyde; PG: Polyglycerol.

[0015] In a first aspect, the present invention provides a method for preparing a benzoxazine marine anticorrosion and antifouling coating, comprising the following steps: S1, paraformaldehyde, 2-aminobenzothiazole and eugenol are mixed and reacted in a first organic solvent, and then cooled and filtered to obtain an intermediate; S2, adding mercaptosiloxane to the intermediate, performing an addition reaction, filtering, and removing the solvent to obtain a siloxane-containing benzoxazine resin; S3, dissolving the benzoxazine resin in a second organic solvent, then adding dropwise the hydrophilic polymer solution, stirring and reacting to obtain a composite component; S4, the composite component is mixed with the organosilicon heat-resistant paint, polycaprolactone and additives to obtain a benzoxazine marine anticorrosion and antifouling coating.

[0016] Preferably, in step S1, the molar ratio of paraformaldehyde, 2-aminobenzothiazole, and eugenol is (2.0-2.3): (1.0-1.2): 1. A slight excess of paraformaldehyde and 2-aminobenzothiazole helps to promote the reaction to completion and improve the yield, while avoiding excessive excess that makes subsequent purification difficult.

[0017] Preferably, in step S1, the mixing reaction is carried out at 100-120° C. for 11-13 hours.

[0018] Preferably, in step S2, the mercaptosiloxane includes 3-mercaptopropyltrimethoxysilane.

[0019] Preferably, in step S2, the molar ratio of the intermediate to the mercaptosiloxane is 1:(1.0-1.3). In the present invention, a slight excess of mercaptosiloxane ensures complete reaction of the intermediate, increasing the reaction rate and yield, thereby maximizing the yield of the target product. Furthermore, mercaptosiloxane is easy to purify; after the reaction, excess silane can be relatively easily removed by methods such as distillation, washing, or column chromatography.

[0020] Preferably, in step S2, the addition reaction is carried out under a nitrogen atmosphere or under conditions of a photoinitiator and ultraviolet light irradiation; the temperature of the addition reaction is 40-60°C and the time is 5-7 hours. In the present invention, the addition reaction is carried out under a nitrogen atmosphere or under conditions of a photoinitiator and ultraviolet light irradiation, both of which can be used to introduce siloxane groups into the benzoxazine resin. Among them, the photoinitiated reaction is more preferred and has a higher yield.

[0021] Further preferably, the photoinitiator includes 1173 photoinitiator; the amount of the photoinitiator used is 0.5 to 1.5% of the total mass of the intermediate and mercaptosiloxane.

[0022] Preferably, in step S3, the ratio of the benzoxazine resin to the second organic solvent is 0.01 mol: (15-25) mL.

[0023] Preferably, in step S3, the hydrophilic polymer solution is prepared by dissolving a hydrophilic polymer in methanol, and the mass concentration of the hydrophilic polymer is 10-25%; the volume ratio of the mixed solution obtained by dissolving the benzoxazine resin in the second organic solvent to the hydrophilic polymer solution is (1.5-2.5):1.

[0024] More preferably, the hydrophilic high molecular polymer includes polyethylene glycol or polyglycerol; and the hydrophilic high molecular polymer solution further contains 3-5 mmol / mL of CuCl2 or ZnCl2.

[0025] Preferably, in step S3, the stirring reaction temperature is 40-50° C. and the time is 11-13 h.

[0026] Preferably, in step S4, the mass ratio of the composite component to the organosilicon heat-resistant paint is 1:3.

[0027] Preferably, in step S4, the heat-resistant silicone paint is WT300 heat-resistant silicone paint, produced by Wuhan Guoqi Co., Ltd.

[0028] Preferably, in step S4, the amount of polycaprolactone added is 5 to 15 wt % of the total mass of the composite component and the organic silicon heat-resistant paint.

[0029] Preferably, in step S4, the auxiliary agent includes at least one of a defoaming agent, a leveling agent and a dispersant.

[0030] Preferably, in step S4, the mixing reaction is carried out by stirring at 60-70° C. for 0.5-1.5 h.

[0031] Preferably, the first organic solvent and the second organic solvent both comprise anhydrous chloroform.

[0032] In a second aspect, the present invention provides a benzoxazine marine anticorrosion and antifouling coating prepared by the above preparation method.

[0033] In a third aspect, the present invention provides a benzoxazine marine anticorrosion and antifouling coating, which is formed by curing the above-mentioned benzoxazine marine anticorrosion and antifouling coating.

[0034] Preferably, the curing conditions include: pre-curing at 70-90° C. for 0.8-1.2 h, and then final curing at 170-190° C. for 0.8-1.2 h.

[0035] The main mechanism of action and advantages of the present invention: 1. The present invention generates a benzothiazolylbenzoxazine resin by cross-linking paraformaldehyde, 2-aminobenzothiazole, and eugenol. The present invention successfully introduces a benzothiazole derivative into the benzoxazine resin system, resulting in a tighter cross-linking method and higher resistance to penetration by corrosive media. Furthermore, while single benzothiazole mixed with a water-based polymer such as polyethylene glycol exhibits poor adhesion and easy detachment after curing, the synthesized benzothiazolylbenzoxazine resin inherits the corrosion resistance of benzothiazole while retaining the resin's inherent zero shrinkage upon curing, good mechanical properties, and electrochemical corrosion resistance.

[0036] 2. The present invention uses mercaptosiloxane to introduce siloxane groups into the benzoxazine resin system by adding mercapto groups to the double bonds on eugenol to perform silicon modification. This can improve the cross-linking degree of the resin after polymerization, reduce the surface energy of the resin, and impart strong hydrophobicity to it, thereby inhibiting the nonspecific adsorption of marine organisms.

[0037] 3. To address the shortcomings of hydrophobic silicone coatings, such as poor adhesion and poor mechanical properties, the present invention introduces polycaprolactone (PCL) with high adhesion as a filler to form a uniform, dense and smooth coating, thereby improving the coating's flexibility and impact resistance, and its performance is superior to that of traditional epoxy-based coatings.

[0038] 4. This invention combines a hydrophobic antifouling coating with a PEG or polyglycerol antifouling coating for the first time, creating an amphiphilic coating. The amphiphilic structure creates a dynamic surface: the hydrophobic domains inhibit microbial adhesion, while the hydrophilic segments reduce biofilm formation through a hydration layer, achieving >95% inhibition of algae, barnacles, and other organisms. This combination allows the coating to kill marine microorganisms that adhere to it while also reducing the attachment of larger marine organisms, achieving a synergistic antifouling effect. It also ensures controlled release of the active ingredients, minimizing environmental impact while maintaining biodegradability, meeting the urgent global demand for sustainable marine coatings.

[0039] Therefore, the present invention provides a marine paint coating with a new antifouling and anticorrosion strategy. The preparation method is simple. The amphiphilic structure of the coating gives this composite material a long-lasting antifouling property, aiming to integrate antifouling, anticorrosion and other protective properties into a system, thereby improving the overall efficiency.

[0040] The present invention is further described in detail below through specific examples.

[0041] Example 1 S1. PFA (n=10) and 2-aminobenzothiazole were mixed and dissolved in anhydrous chloroform. Eugenol was slowly added dropwise with stirring, and the molar ratio of PFA:2-aminobenzothiazole:eugenol was controlled to be 2:1:1. The mixture was reacted at 110°C for 12 hours, cooled to room temperature, and filtered to obtain a uniform, transparent, yellow, viscous intermediate.

[0042] S2. Add 3-mercaptopropyltrimethoxysilane in an equal molar ratio to the intermediate and 1% of the total weight of the photoinitiator (1173) to the intermediate, react under ultraviolet light at 50°C for 6 hours, and then remove the solvent by negative pressure evaporation after vacuum filtration to obtain component A (benzoxazine resin).

[0043] S3, component A (0.01 mol) was dissolved in anhydrous chloroform (20 mL) to form a benzoxazine-chloroform mixture, and a 10 wt% polyethylene glycol-methanol mixed solution was added dropwise at a volume ratio of 2:1. The mixture was reacted at 45°C for 12 hours to obtain a composite component B.

[0044] S4, by mass, mixed 25 parts of composite component B with 75 parts of silicone heat-resistant paint (WT300), and then added 5 parts of PCL, 1 part of defoamer (Silok-4010), 1 part of leveling agent (Silok-350), and 2 parts of dispersant (Silok-7066) in that order. After homogenization at 65°C for 1 hour, the mixture was pre-cured at 80°C for 1 hour and finally cured at 180°C for 1 hour to complete the preparation.

[0045] Example 2 Compared with Example 1, the only difference is that 20 wt % polyethylene glycol-methanol mixed solution is added dropwise in step S3, and the other steps and conditions are the same as those in Example 1.

[0046] Example 3 Compared with Example 1, the only difference is that 25 wt % polyethylene glycol-methanol mixed solution is added dropwise in step S3, and the other steps and conditions are the same as those in Example 1.

[0047] Example 4 Compared with Example 1, the only difference is that in step S3, the 10 wt % polyethylene glycol-methanol mixed solution is replaced by a 10 wt % polyglycerol (PG)-methanol solution, and the other steps and conditions are the same as those in Example 1.

[0048] Example 5 Compared with Example 1, the only difference is that in step S3, the 10 wt % polyethylene glycol-methanol mixed solution is replaced by a 20 wt % polyglycerol (PG)-methanol solution, and the other steps and conditions are the same as those in Example 1.

[0049] Example 6 Compared with Example 1, the only difference is that in step S3, the 10 wt % polyethylene glycol-methanol mixed solution is replaced by a 25 wt % polyglycerol (PG)-methanol solution, and the other steps and conditions are the same as those in Example 1.

[0050] Example 7 S1. PFA (n=10) and 2-aminobenzothiazole were mixed and dissolved in anhydrous chloroform. Eugenol was slowly added dropwise with stirring, and the molar ratio of PFA:2-aminobenzothiazole:eugenol was controlled to be 2:1:1. The mixture was reacted at 110°C for 12 hours, cooled to room temperature, and filtered to obtain a uniform, transparent, yellow, viscous intermediate.

[0051] S2. Add 3-mercaptopropyltrimethoxysilane in an equal molar ratio to the intermediate and 1% of the total weight of the photoinitiator (1173) to the intermediate, react under ultraviolet light at 50°C for 6 hours, and then remove the solvent by negative pressure evaporation after vacuum filtration to obtain component A (benzoxazine resin).

[0052] In step S3, component A (0.01 mol) was dissolved in anhydrous chloroform (20 mL) to form a benzoxazine-chloroform mixture. CuCl2 (0.04 mol) was dissolved in methanol (10 mL), and 10% polyethylene glycol (PEG) by weight of methanol was slowly added to form a CuCl2-10 wt% PEG-methanol mixed solution. The CuCl2-10 wt% PEG-methanol mixed solution was slowly added dropwise to the benzoxazine-chloroform mixture. The mixture was stirred at 50°C for 12 hours to obtain composite component B.

[0053] S4, by mass, mixed 25 parts of composite component B with 75 parts of silicone heat-resistant paint (WT300), and then added 5 parts of PCL, 1 part of defoamer (Silok-4010), 1 part of leveling agent (Silok-350), and 2 parts of dispersant (Silok-7066) in that order. After homogenization at 65°C for 1 hour, the mixture was pre-cured at 80°C for 1 hour and finally cured at 180°C for 1 hour to complete the preparation.

[0054] Example 8 Compared with Example 7, the only difference is that in step S3, CuCl2 is replaced by ZnCl2, and the other steps and conditions are the same as those in Example 7.

[0055] Example 9 Compared with Example 1, the only difference is that in step S4, the amount of PCL added is adjusted to 10 parts, and the other steps and conditions are the same as those in Example 1.

[0056] Example 10 Compared with Example 1, the only difference is that in step S4, the amount of PCL added is adjusted to 15 parts, and the other steps and conditions are the same as those in Example 1.

[0057] Performance testing: 1. Coating mechanical properties test According to the national standards GB / T1720-1979 (1989), GB / T1732-1993, GB / T6739-2006 and GB / T 13452.2-2008, the adhesion, impact resistance, thickness and hardness of the coatings of Examples 1-3, 4, 7-8 were comprehensively tested using the circle method, frontal impact test, pencil hardness tester and mechanical method. The performance data are detailed in Table 1.

[0058] Table 1 Mechanical test diagrams of different coatings

[0059] As can be seen from Table 1, in Examples 1-3, by changing the content of the hydrophilic polymer, as the content of the hydrophilic polymer increases, the hardness and impact resistance of the obtained coatings decrease slightly, but the adhesion increases.

[0060] In Example 4, the type of hydrophilic high molecular polymer was changed from PEG in Example 1 to polyglycerol, and its mechanical properties were substantially the same as those in Example 1.

[0061] In Examples 7-8, active ingredients CuCl2 and ZnCl2 were introduced, and the reaction temperature was slightly increased. The adhesion of the coating finally obtained was improved compared with Example 1, and the impact resistance was better when CuCl2 was used.

[0062] The mechanical strength of Example 1 and Examples 9-10 was tested according to the national standard GB / T1931-1993.

[0063] Examples 1, 9, and 10 investigated the effects of varying PCL content on the mechanical properties of the composite coatings. The mechanical strength of each coating decreased with increasing PCL content, but the elongation at break increased. The tensile strength increased from 1.476 MPa with 5 wt% PCL (relative to the total amount of composite component B and the silicone heat-resistant paint) to 0.641 MPa with 15% PCL. The Young's modulus decreased from 2.136 MPa to 0.604 MPa, while the elongation at break increased from 69.1% to 106.2%. Because PCL has relatively poor mechanical strength but exhibits superior flexibility and ductility, its addition to the composite coating reduces the coating's mechanical strength while enhancing its flexibility and ductility.

[0064] 2. Antibacterial Experiment Staphylococcus aureus and Escherichia coli were activated at 37°C for 2 hours and then cultured in nutrient broth for 20 hours. A layer of coating was applied to a 24-well plate and sterilized with UV for 2 hours. 6 Each experimental group contained three replicates of a 1 mL bacterial solution containing 100 CFU / mL. The material was co-cultured with the bacteria for 12 hours. The bacterial solution (40 μL) was then evenly applied to the solid culture medium. After complete absorption, the medium was incubated at 37°C for 18 hours. The inhibition rate was determined using formula (1).

[0065] Formula (1) Where, S is the inhibition rate, S o is the average colony count of the control group, S i is the average colony number of the experimental group.

[0066] Antibacterial results such as Figure 1 As shown, where: (a) is a blank sample, which is a plate without any coating for the antibacterial test against Staphylococcus aureus; (b), (c), (d), and (e) are experimental groups, in which the well plates coated with the coatings of Examples 1, 2, 3, and 4 were used for antibacterial experiments on Staphylococcus aureus; (f) is a blank sample, which is a plate without any coating for the antibacterial test against Escherichia coli; (g), (h), (i), and (j) are experimental groups, which were coated with the coatings of Examples 1, 2, 3, and 4, respectively, and subjected to antibacterial experiments against E. coli. The specific antibacterial results are shown in Table 2 below.

[0067] Table 2 Antibacterial test results

[0068] The results showed that the product of the present invention has a good antibacterial effect, with an inhibition rate of over 90% against Staphylococcus aureus and an inhibition rate of over 78% against Escherichia coli. The antibacterial test of the material concluded that the addition of 20 wt% and 25 wt% of a hydrophilic polymer gave the composite material better antibacterial properties. The addition of a hydrophilic polymer solved the problem of antibacterial properties of the polybenzoxazine resin material. In addition, Examples 1 and 4 compared the effects of different hydration layers on antimicrobial adhesion by varying the hydrophilic polymer. It was concluded that the antimicrobial adhesion ability of the coating after curing with polyethylene glycol (PEG) was better than that of polyglycerol (PG). The coating prepared with polyethylene glycol is preferred in the present invention.

[0069] 3. Anti-algae experiment Using a UV-visible spectrophotometer to scan in the range of 800 nm-200 nm, the maximum UV absorption wavelength of P. tricornutum was found to be 682 nm.

[0070] Anti-algae results such as Figure 2 As shown, where: (a) and (e) are blank samples, which are glass plates without any polymers after co-culture with algae for 0 and 7 days, respectively; (b) and (f) are experimental group 1, which are glass plates coated with Example 1 and co-cultured with algae for 0 and 7 days, respectively; (c) and (g) are experimental group 2, which are glass plates coated with Example 7 and co-cultured with algae for 0 and 7 days, respectively; (d) and (h) are experimental group 3, which are glass plates coated with Example 8 and co-cultured with algae for 0 and 7 days, respectively; The results show that after 7 days of co-culture of the coating with algae, the inhibitory effects of the blank sample, Examples 1, 7 and 8 on algae showed significant differences. The inhibition rates of Examples 1, 7 and 8 on P. triangularis were 64.05%, 90.64% and 89.73%, respectively. The culture medium of the blank coating turned yellow-green and a large amount of yellow-green precipitate appeared, indicating algal cell proliferation. In contrast, the culture medium coated with the coating of the present invention was clear and transparent, with no obvious algal cell proliferation and extremely low algal cell growth activity, which indicates that the Cu released by the composite coating of the present invention is 2+ and Zn 2+ The concentration of the present invention only inhibits the proliferation of algal cells without causing the death of algal cells. Therefore, the coating of the present invention is a potential environmentally friendly marine antifouling material.

[0071] 4. Salt spray test After coating the coatings of Examples 1, 2 and 3 on the steel plates, the corrosion results are as follows: Figure 3 As shown, where: (a) is a blank sample, which is a digital photo of a mild steel plate without any coating; (b), (c), and (d) are digital photos of the experimental groups, which are low-carbon steel plates coated with Examples 1, 2, and 3, respectively; (e) is a digital photo of the control group, which is a mild steel plate without any coating after a 168-h salt spray test with 3.5wt% NaCl solution; (f), (g), and (h) are digital photos of the experimental groups, which are low-carbon steel plates coated with Examples 1, 2, and 3, respectively, after undergoing a 168-h salt spray test with a 3.5 wt% NaCl solution.

[0072] Depend on Figure 3 It can be seen that after 168 hours of salt spray test with 3.5wt% NaCl solution, the steel plate coated with the coating of the present invention was basically not corroded, and corrosion only occurred at the scratches. This is because the steel plate at the scratches was directly exposed to the salt spray. The control group shown in Figure (e) showed obvious corrosion. It can be concluded that the coating of the present invention has good corrosion resistance and can withstand salt spray erosion for at least 168 hours.

[0073] 5. Ion release rate test Depend on Figure 4 The test results of ion release rate of different coatings in artificial seawater at room temperature show that the composite coating has a 2+ and Zn 2+ The composite coating has good controlled release performance, and its release rate tends to be stable within 7 days. It can be seen that during the ion release rate measurement, the ion release rate of the composite coating remains at 30-70 μg cm -2 day -1The release rate is within the range of 1.5 wt % and is consistent with the release rate of traditional marine antifouling coatings.

[0074] The specific embodiments of the present invention described above do not limit the scope of protection of the present invention. Any other corresponding changes and modifications made based on the technical concept of the present invention should be included in the scope of protection of the claims of the present invention.

Claims

1. A method for preparing a benzoxazine marine anticorrosion and antifouling coating, characterized in that: The following steps are involved: S1, paraformaldehyde, 2-aminobenzothiazole and eugenol are mixed and reacted in a first organic solvent, and then cooled and filtered to obtain an intermediate; S2, adding mercaptosiloxane to the intermediate, performing an addition reaction, filtering, and removing the solvent to obtain a siloxane-containing benzoxazine resin; S3, dissolving the benzoxazine resin in a second organic solvent, adding a hydrophilic polymer solution dropwise, and stirring to react to obtain a composite component; S4, the composite component is mixed with the organosilicon heat-resistant paint, polycaprolactone and an additive to react to obtain a benzoxazine marine anticorrosion and antifouling coating.

2. The method for preparing the benzoxazine marine anticorrosion and antifouling coating according to claim 1, characterized in that: In step S1, the molar ratio of paraformaldehyde, 2-aminobenzothiazole and eugenol is (2.0-2.3): (1.0-1.2): 1; and / or, The mixing reaction is carried out at 100-120° C. for 11-13 hours.

3. The method for preparing the benzoxazine marine anticorrosion and antifouling coating according to claim 1, characterized in that: In step S2, the mercaptosiloxane includes 3-mercaptopropyltrimethoxysilane; and / or, The molar ratio of the intermediate to the mercaptosiloxane is 1:(1.0-1.3).

4. The method for preparing the benzoxazine marine anticorrosion and antifouling coating according to claim 1, characterized in that: In step S2, the addition reaction is carried out under a nitrogen atmosphere, or under the conditions of a photoinitiator and ultraviolet light irradiation; the temperature of the addition reaction is 40 to 60° C., and the time is 5 to 7 hours; The photoinitiator includes 1173 photoinitiator; the amount of the photoinitiator is 0.5-1.5% of the total mass of the intermediate and mercaptosiloxane.

5. The method for preparing the benzoxazine marine anticorrosion and antifouling coating according to claim 1, characterized in that: In step S3, the ratio between the benzoxazine resin and the second organic solvent is 0.01 mol: (15-25) mL; and / or, The hydrophilic polymer solution is prepared by dissolving a hydrophilic polymer in methanol, and the mass concentration of the hydrophilic polymer is 10-25%; and / or, The volume ratio of the mixed solution obtained by dissolving the benzoxazine resin in the second organic solvent to the hydrophilic polymer solution is (1.5-2.5):1; and / or, The stirring reaction in step S3 is carried out at a temperature of 40 to 50° C. and for a time of 11 to 13 hours.

6. The method for preparing the benzoxazine marine anticorrosion and antifouling coating according to claim 5, characterized in that: The hydrophilic high molecular polymer includes polyethylene glycol or polyglycerol; the hydrophilic high molecular polymer solution also contains 3-5 mmol / mL of CuCl2 or ZnCl2.

7. The method for preparing the benzoxazine marine anticorrosion and antifouling coating according to claim 1, characterized in that: In step S4, the mass ratio of the composite component to the organic silicon heat-resistant paint is 1:(2.5-3.5); and / or, The amount of polycaprolactone added is 5-15% of the total mass of the composite component and the organic silicon heat-resistant paint; and / or, The auxiliary agent includes at least one of a defoamer, a leveling agent and a dispersant; and / or, The mixing reaction in step S4 is carried out by stirring at 60-70° C. for 0.5-1.5 h.

8. A benzoxazine marine anticorrosion and antifouling coating prepared according to the preparation method according to any one of claims 1 to 7.

9. A benzoxazine marine anticorrosion and antifouling coating, characterized in that: The benzoxazine marine anticorrosion and antifouling coating is formed by curing the benzoxazine marine anticorrosion and antifouling coating according to claim 8.

10. The benzoxazine marine anticorrosion and antifouling coating according to claim 9, characterized in that: The curing conditions include: pre-curing at 70-90° C. for 0.8-1.2 hours, and then final curing at 170-190° C. for 0.8-1.2 hours.

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