Chloroacetic acid modified epoxy resin precursor, marine antifouling paint and application

Abstract

The invention discloses a chloroacetic acid modified epoxy resin precursor. The structure of the chloroacetic acid modified epoxy resin precursor is shown as a formula (I) or a formula (II). The invention also discloses a marine antifouling coating, the marine antifouling coating is obtained by carrying out gradient curing reaction on the chloroacetic acid modified epoxy resin precursor and E51 epoxy resin under the action of a curing agent, and the prepared marine antifouling coating structurally contains betaine ester groups and pyrrolidone structures. The marine antifouling paint with the pyrrolidone structure can be subjected to ring opening in a seawater (pH = 8.2) environment, and hydrolysis of ester bonds is promoted by improving hydrophilicity and influencing near ester bond electron cloud density, so that the marine antifouling paint has seawater degradability. In addition, ester bonds in betaine ester groups can also be hydrolyzed in seawater. Secondly, the betaine ester group has the non-specific bactericidal activity of quaternary ammonium salt. The formula (I) and the formula (II) are shown in the description.

Description

Technical Field

[0001] This invention relates to the field of coating technology, specifically to a chloroacetic acid-modified epoxy resin precursor, a marine antifouling coating, and its applications. Background Technology

[0002] In the process of developing and utilizing marine resources, ships and underwater equipment inevitably encounter the problem of marine biofouling. The attachment of fouling organisms increases the roughness of the ship's hull surface, increases the load, thereby increasing navigation resistance and energy consumption; attached fouling organisms, such as barnacles, secrete organic acids and other substances during their metabolism, accelerating the corrosion of offshore platforms or marine infrastructure; biofouling can also clog marine facility pipelines, affecting the normal operation of equipment. Statistics show that my country suffers economic losses of up to 100 billion yuan annually due to marine biofouling. Currently, antifouling coatings are the most effective, economical, and widely used strategy for preventing and controlling marine biofouling.

[0003] Various marine antifouling coatings have been reported, such as biomimetic antifouling coatings, amphiphilic antifouling coatings, fouling resistance antifouling coatings, and antifouling agent release coatings. Among them, self-polishing antifouling coatings, whose surfaces can be self-renewed through the degradation or hydrolysis of film-forming resins in seawater, are the most widely used due to their high antifouling efficiency and long duration of action.

[0004] However, film-forming resins typically lack intrinsic antifouling capabilities, requiring the introduction of substantial amounts of antifouling agents to achieve effective antifouling. Chinese patent document CN118995028A discloses a temperature-controlled release degradation antifouling coating and its preparation method, comprising: Component A, which includes a polyhydroxy degradable polyester copolymer, a temperature-sensitive resin polymer, a composite antifouling agent, a temperature-sensitive gel-coated antifouling agent, an auxiliary antifouling agent, a defoamer, pigments and fillers, an anti-settling agent, and a first solvent; and Component B, which includes a polyisocyanate and a second solvent; the mass ratio of Component A to Component B is 10:0.9–1.2. By using a composite of a degradable polyhydroxy degradable polyester copolymer and a temperature-sensitive resin polymer as the resin base, and simultaneously composited with a temperature-sensitive gel-coated antifouling agent, the coating achieves highly efficient antifouling effects in marine environments at different temperatures.

[0005] Chinese patent document CN116874474A discloses a bio-based biodegradable epoxy resin precursor and a marine antifouling coating, as well as their preparation methods. The bio-based epoxy resin precursor has any of the structures shown in the following formula: Wherein, R is selected from any one of H, CH3, CHCH3CH3, CH2CHCH3CH3, CHCH3CH2CH3, CH2C6H5, and CH2CH2SCH3; n is selected from 1 to 5. The pyrrolidone structure readily undergoes ring-opening under alkaline conditions, promoting ester bond hydrolysis in the weakly alkaline marine environment by increasing hydrophilicity and affecting the electron cloud density of adjacent ester bonds. The material is endowed with biodegradable properties by modifying glycidyl ether epoxy resin with pyrrolidone dicarboxylic acid.

[0006] Currently, the antibacterial effect of existing marine antifouling coatings is generally limited. Therefore, there is an urgent need to find a marine antifouling coating with excellent antibacterial effect to meet the needs of existing technologies. Summary of the Invention

[0007] To address the aforementioned technical problems, this invention provides a chloroacetic acid-modified epoxy resin precursor.

[0008] A chloroacetic acid-modified epoxy resin precursor, the structure of which is shown in formula (I) or formula (II): Equation (I) Formula (II) Where n = 1 to 5.

[0009] In this invention, the epoxy resin precursor modified with chloroacetic acid contains chloroacetic acid groups at its ends, which can further react with tertiary amine curing agents to generate terminal betaine ester structures. These are special quaternary ammonium salts with contact bactericidal properties, capable of disrupting bacterial cell membranes. Therefore, chloroacetic acid modification significantly improves the antibacterial properties of the cured epoxy resin. Simultaneously, the terminal betaine ester structure is easily hydrolyzed under weakly alkaline conditions (such as seawater, pH≈8.0), endowing the resin with controllable degradation capabilities. This solves the environmental problem of traditional epoxy resins being difficult to degrade, making it more suitable for marine and other scenarios requiring environmentally friendly materials.

[0010] The present invention also provides a method for preparing the above-mentioned chloroacetic acid modified epoxy resin precursor, comprising the following steps: (1) After mixing itaconic acid, glycine and water, Michael addition reaction was carried out, followed by washing with organic solvent and filtration to obtain pyrrolidone dicarboxylic acid; (2) After adding ethylene glycol glycidyl ether and accelerator to the pyrrolidone dicarboxylic acid obtained in step (1) for dehydration condensation reaction, epoxy resin containing pyrrolidone structure is obtained. (3) The epoxy resin containing pyrrolidone structure obtained in step (2) is reacted with chloroacetic acid under the action of a catalyst to obtain a chloroacetic acid modified epoxy resin precursor.

[0011] Preferably, in step (1), the molar ratio of itaconic acid to glycine is 1:1~3.

[0012] In this invention, when the molar ratio of itaconic acid and glycine is within the above-mentioned range, the reaction is complete, the yield is high, and the product is easy to purify.

[0013] Preferably, in step (1), the Michael addition reaction is carried out at a temperature of 60-180 °C for 3-14 h. When the reaction conditions are within the above range, the volatilization of reactants is reduced, the reaction rate is higher, and the yield is higher.

[0014] Preferably, in step (1), the organic solvent is at least one selected from hexane, cyclohexane, acetone, petroleum ether, dichloromethane, chloroform, ethyl acetate, tetrahydrofuran, dioxane, and diethyl ether.

[0015] In this invention, the organic solvent is selected to have good solubility for the product pyrrolidone dicarboxylic acid, making it easy to extract pyrrolidone dicarboxylic acid.

[0016] Preferably, in step (2), the molar ratio of pyrrolidone dicarboxylic acid and ethylene glycol glycidyl ether is 1:3~18.

[0017] Preferably, in step (2), the accelerator is triphenylphosphine, and the amount of the accelerator added is 1 wt% to 5 wt% of the total mass of pyrrolidone dicarboxylic acid and ethylene glycol glycidyl ether.

[0018] Preferably, in step (2), the temperature of the dehydration condensation reaction is 80~200 ℃ and the time is 3~8 h.

[0019] Preferably, in step (3), the molar ratio of chloroacetic acid to epoxy resin containing pyrrolidone structure is 1:3~18.

[0020] In this invention, when the above molar ratio is too low, the degree of chloroacetic acid modification is too high, the degradation rate of the prepared marine antifouling coating is too fast, and it is easy to swell, leading to the aging of the coating. When the molar ratio is too high, the prepared marine antifouling coating is not easy to degrade.

[0021] Preferably, in step (3), the catalyst is at least one of p-toluenesulfonic acid, methanesulfonic acid, trifluoromethanesulfonic acid, benzenesulfonic acid, p-nitrobenzenesulfonic acid, boron trifluoride, etc.

[0022] In this invention, the catalyst described above has good solubility and can promote a stable reaction.

[0023] More preferably, in step (3), the amount of catalyst added is 1 wt% to 5 wt% of the total mass of the epoxy resin containing the pyrrolidone structure and chloroacetic acid.

[0024] Preferably, in step (3), the reaction temperature is 60~180 ℃ and the reaction time is 12~36 h.

[0025] The present invention also provides a marine antifouling coating, which is obtained by subjecting the above-mentioned chloroacetic acid modified epoxy resin precursor and E51 epoxy resin to a gradient curing reaction under the action of a curing agent.

[0026] In this invention, the prepared marine antifouling coating contains betaine ester groups and pyrrolidone structures. The pyrrolidone structure allows for ring-opening in seawater (pH=8.2), promoting ester bond hydrolysis by increasing hydrophilicity and influencing the electron cloud density of adjacent ester bonds. Therefore, this marine antifouling coating is seawater degradable. Furthermore, the ester bonds in the betaine ester group can also hydrolyze in seawater. Secondly, the betaine ester group exhibits non-specific bactericidal activity of quaternary ammonium salts. Simultaneously, when compounded with commercially available E51 epoxy resin, it imparts advantages such as strong adhesion, good film-forming properties, good flexibility, and other good mechanical properties, making it suitable as a resin matrix for self-polishing marine antifouling coatings.

[0027] Preferably, the mass ratio of the chloroacetic acid-modified epoxy resin precursor to the E51 epoxy resin is 1:0.1~6.

[0028] In this invention, when the mass ratio is too low, the marine antifouling coating degrades too quickly, and the mechanical properties of the coating formed by the coating are poor. When the mass ratio is too high, the marine antifouling coating is not easily degraded, and the crosslinking density of the coating formed by the coating is too high.

[0029] Preferably, the curing agent is a tertiary amine curing agent or an epoxy curing agent.

[0030] More preferably, the tertiary amine curing agent is at least one selected from 2,4,6-tris(dimethylaminomethyl)phenol (DMP), 1,1,1-trimethylpropane tri-[3(diethylamine)propionate] (TMP), benzyl dimethylamine (BDMA), dimethylaminopropylamine (DMAPA), triethylamine (TEA), and N,N-dimethylcyclohexylamine (DMCHA); and the epoxy curing agent is at least one selected from phthalic anhydride, tetrahydrophthalic anhydride, methylhexahydrophthalic anhydride, diethylenetriamine, tetraethylenepentamine, ethylenediamine, hexamethylenediamine, isophorone diamine, 4,4'-diaminodiphenyl sulfone, and 4,4'-diaminodiphenylmethane.

[0031] Preferably, the mass ratio of the curing agent to the total mass of the chloroacetic acid-modified epoxy resin precursor and E51 epoxy resin is 8~54:100, wherein the mass ratio of the tertiary amine curing agent to the epoxy curing agent is 1~5:1~8.

[0032] Preferably, the gradient curing starts at 60°C and ends at 120°C.

[0033] Preferably, the marine antifouling coating has an intrinsic bactericidal effect, and the bactericidal rate of the marine antifouling coating against Staphylococcus aureus and Escherichia coli is ≥95%.

[0034] Compared with the prior art, the present invention has the following beneficial effects: The marine antifouling coating obtained by combining a chloroacetic acid-modified epoxy resin precursor with E51 epoxy resin under the action of a curing agent in this invention contains betaine ester groups and pyrrolidone groups. In the weakly alkaline environment of the ocean, the betaine ester group and pyrrolidone structure can increase the hydrophilicity of the material. In the weakly alkaline environment, the pyrrolidone structure increases hydrophilicity through ring-opening hydrolysis and affects the electron density of the electron cloud of adjacent ester bonds, thereby promoting the hydrolysis of ester bonds and forming a self-renewing surface. In addition, betaine ester, as a special quaternary ammonium salt structure, can achieve non-specific bactericidal effects and is effective against a variety of microorganisms such as bacteria, viruses, yeasts, fungi, and protozoa. Furthermore, the coating, after being mixed with commercial E51 epoxy resin, also exhibits excellent film-forming properties, adhesion, and impact strength, meeting the requirements for long-term use. Attached Figure Description

[0035] Figure 1 The infrared spectra of the epoxy resin precursors of Examples 1, 1, and 2 before curing are shown.

[0036] Figure 2 The infrared spectra of Example 1 before and after curing are compared.

[0037] Figure 3 The images show a comparison of the morphology of the marine antifouling coating prepared in Example 2 and the coating 2 in Comparative Example 2 before and after immersion in seawater for 2 weeks.

[0038] Figure 4 The antibacterial rates of Examples 1-3 and Comparative Examples 1 and 2 against Escherichia coli and Staphylococcus aureus are statistically shown. Detailed Implementation

[0039] The present invention will be further described in detail below with reference to the embodiments, but the implementation of the present invention is not limited to the following embodiments.

[0040] All raw materials used in this invention are commercially available.

[0041] Example 1 (1) Dissolve 130.11 g of itaconic acid and 75.08 g of glycine in 100 mL of water and heat to 90 °C to ensure complete dissolution. Then, use a vacuum pump to evacuate and dehydrate the reaction system until no water is present. After cooling to room temperature, add acetone to the reaction mixture to dissolve the product. Pour the resulting solution into petroleum ether and let it precipitate overnight. Stir, disperse, filter, and wash three times with ethyl acetate. Finally, collect the white powdery product, pyrrolidone dicarboxylic acid, after vacuum drying.

[0042] (2) 10 g of pyrrolidone dicarboxylic acid, 100 g of ethylene glycol glycidyl ether, and 1 wt‰ of triphenylphosphine accelerator were heated to 100°C and stirred in an oil bath for 4 hours. After the reaction was completed, an epoxy resin containing a pyrrolidone structure was obtained.

[0043] (3) 10 g of chloroacetic acid, 50 g of epoxy resin containing a pyrrolidone structure, and 0.6 g of p-toluenesulfonic acid catalyst were reacted under a nitrogen atmosphere at 100°C with stirring in an oil bath for 24 hours. After the reaction was completed, a chloroacetic acid-modified epoxy resin precursor was obtained. Figure 1 As shown, the chloroacetic acid-modified epoxy resin precursor at 852 cm⁻¹ -1 The weakening of the characteristic absorption band of the nearby epoxy group, 1710 cm -1 The significant enhancement of the OC=O absorption band at 3500 cm⁻¹ and the 3500 cm⁻¹ absorption band. -1 The enhanced hydroxyl absorption band indicates that the modification was successful.

[0044] (4) After uniformly mixing 6 g of chloroacetic acid-modified epoxy resin precursor with 14 g of E51 epoxy resin, it is then mixed with 2.6212 g of DMP and 2.5365 g of 4,4'-diaminodicyclohexylmethane (PACM). The mixture is then applied evenly to a resin plate or tinplate using a coating applicator. The mixture is cured in an oven at 60°C, 80°C, 100°C, and 120°C for two hours each to obtain a marine antifouling coating. Figure 2 The epoxy resin shown is 1250 cm after curing. -1 Enhanced CN absorption band at 1710 cm⁻¹ and at 1710 cm⁻¹ -1 The enhanced absorption band of the nearby ester bond corresponds to the formation of the betaine ester group structure.

[0045] Example 2 (1) Pyrrolidone dicarboxylic acid was prepared in the same manner as in Example 1.

[0046] (2) In the same manner as in Example 1, an epoxy resin containing a pyrrolidone structure was prepared.

[0047] (3) 15 g of chloroacetic acid, 50 g of epoxy resin containing pyrrolidone structure, and 0.65 g of p-toluenesulfonic acid catalyst were heated to 100 °C under a nitrogen atmosphere and stirred in an oil bath for 24 hours. After the reaction was completed, chloroacetic acid modified epoxy resin precursor was obtained.

[0048] (4) Mix 10 g of chloroacetic acid modified epoxy resin precursor, 15 g of E51 epoxy resin, 2.8084 g of DMP and 1.6241 g of 4,4'-diaminodicyclohexylmethane (PACM) thoroughly and evenly, and then coat it evenly on a resin plate or tinplate sheet with a coating tool. Cur the coating in an oven at 60℃, 80℃, 100℃ and 120℃ for two hours respectively to obtain marine antifouling coating.

[0049] Example 3 (1) Pyrrolidone dicarboxylic acid was prepared in the same manner as in Example 1.

[0050] (2) In the same manner as in Example 1, an epoxy resin containing a pyrrolidone structure was prepared.

[0051] (3) 5 g of chloroacetic acid, 50 g of epoxy resin containing pyrrolidone structure, and 0.55 g of p-toluenesulfonic acid catalyst were heated to 100°C under a nitrogen atmosphere and stirred in an oil bath for 24 hours. After the reaction was completed, chloroacetic acid modified epoxy resin precursor was obtained.

[0052] (4) 10 g of chloroacetic acid modified epoxy resin precursor, 5 g of E51 epoxy resin, 0.9361 g of DMP and 2.1432 g of 4,4'-diaminodicyclohexylmethane (PACM) were mixed thoroughly and evenly, and then evenly coated onto a resin plate or tinplate using a coating tool. The mixture was cured in an oven at 60°C, 80°C, 100°C and 120°C for two hours respectively to obtain a marine antifouling coating.

[0053] Example 4 (1) Pyrrolidone dicarboxylic acid was prepared in the same manner as in Example 1.

[0054] (2) In the same manner as in Example 1, an epoxy resin containing a pyrrolidone structure was prepared.

[0055] (3) 10 g of chloroacetic acid, 50 g of epoxy resin containing pyrrolidone structure, and 0.60 g of p-toluenesulfonic acid catalyst were heated to 100°C under a nitrogen atmosphere and stirred in an oil bath for 24 hours. After the reaction was completed, chloroacetic acid modified epoxy resin precursor was obtained.

[0056] (4) 10 g of chloroacetic acid modified epoxy resin precursor, 20 g of E51 epoxy resin, 2.6212 g of DMP and 1.9531 g of 4,4'-diaminodicyclohexylmethane (PACM) were mixed thoroughly and evenly, and then evenly coated onto resin plate or tinplate sheet with a coating tool. The mixture was cured in an oven at 60℃, 80℃, 100℃ and 120℃ for two hours respectively to obtain marine antifouling coating.

[0057] Example 5 (1) Pyrrolidone dicarboxylic acid was prepared in the same manner as in Example 1.

[0058] (2) In the same manner as in Example 1, an epoxy resin containing a pyrrolidone structure was prepared.

[0059] (3) 10 g of chloroacetic acid, 50 g of epoxy resin containing pyrrolidone structure, and 0.60 g of p-toluenesulfonic acid catalyst were heated to 100°C under a nitrogen atmosphere and stirred in an oil bath for 24 hours. After the reaction was completed, chloroacetic acid modified epoxy resin precursor was obtained.

[0060] (4) 10 g of chloroacetic acid modified epoxy resin precursor, 25 g of E51 epoxy resin, 2.6212 g of DMP and 2.4538 g of 4,4'-diaminodicyclohexylmethane (PACM) were mixed thoroughly and evenly, and then evenly coated onto a resin plate or tinplate using a coating tool. The mixture was cured in an oven at 60°C, 80°C, 100°C and 120°C for two hours respectively to obtain a marine antifouling coating.

[0061] Example 6 (1) Pyrrolidone dicarboxylic acid was prepared in the same manner as in Example 1.

[0062] (2) In the same manner as in Example 1, an epoxy resin containing a pyrrolidone structure was prepared.

[0063] (3) 10 g of chloroacetic acid, 50 g of epoxy resin containing pyrrolidone structure, and 0.60 g of p-toluenesulfonic acid catalyst were heated to 100°C under a nitrogen atmosphere and stirred in an oil bath for 24 hours. After the reaction was completed, chloroacetic acid modified epoxy resin precursor was obtained.

[0064] (4) Mix 10 g of chloroacetic acid modified epoxy resin precursor with 10 g of E51 epoxy resin, 2.9765 g of DMP and 2.5365 g of 4,4'-diaminodicyclohexylmethane (PACM) thoroughly and evenly, and then coat it evenly on a resin plate or tinplate sheet with a coating tool. Cur the coating in an oven at 60℃, 80℃, 100℃ and 120℃ for two hours respectively to obtain marine antifouling coating.

[0065] Example 7 (1) Pyrrolidone dicarboxylic acid was prepared in the same manner as in Example 1.

[0066] (2) In the same manner as in Example 1, an epoxy resin containing a pyrrolidone structure was prepared.

[0067] (3) 10 g of chloroacetic acid, 50 g of epoxy resin containing pyrrolidone structure, and 0.60 g of p-toluenesulfonic acid catalyst were heated to 100°C under a nitrogen atmosphere and stirred in an oil bath for 24 hours. After the reaction was completed, chloroacetic acid modified epoxy resin precursor was obtained.

[0068] (4) Mix 10 g of chloroacetic acid modified epoxy resin precursor with 10 g of E51 epoxy resin, 2.6212 g of DMP and 1.9325 g of 4,4'-diaminodicyclohexylmethane (PACM) thoroughly and evenly, and then coat it evenly on a resin plate or tinplate with a coating tool. Cur the coating in an oven at 60℃, 80℃, 100℃ and 120℃ for two hours respectively to obtain marine antifouling coating.

[0069] Example 8 (1) Pyrrolidone dicarboxylic acid was prepared in the same manner as in Example 1.

[0070] (2) In the same manner as in Example 1, an epoxy resin containing a pyrrolidone structure was prepared.

[0071] (3) 10 g of chloroacetic acid, 50 g of epoxy resin containing pyrrolidone structure, and 0.60 g of p-toluenesulfonic acid catalyst were heated to 100°C under a nitrogen atmosphere and stirred in an oil bath for 24 hours. After the reaction was completed, chloroacetic acid modified epoxy resin precursor was obtained.

[0072] (4) Mix 10 g of chloroacetic acid modified epoxy resin precursor with 10 g of E51 epoxy resin, 0.9765 g of dimethylaminopropylamine (DMAPA) and 2.5365 g of 4,4'-diaminodicyclohexylmethane (PACM) thoroughly and evenly, and then coat it evenly on a resin plate or tinplate with a coating tool. Cur the coating in an oven at 60℃, 80℃, 100℃ and 120℃ for two hours respectively to obtain a marine antifouling coating.

[0073] Example 9 (1) Pyrrolidone dicarboxylic acid was prepared in the same manner as in Example 1.

[0074] (2) In the same manner as in Example 1, an epoxy resin containing a pyrrolidone structure was prepared.

[0075] (3) 10 g of chloroacetic acid, 50 g of epoxy resin containing pyrrolidone structure, and 0.06 g of p-toluenesulfonic acid catalyst were heated to 100°C under a nitrogen atmosphere and stirred in an oil bath for 24 hours. After the reaction was completed, chloroacetic acid modified epoxy resin precursor was obtained.

[0076] (4) Mix 10 g of chloroacetic acid modified epoxy resin precursor with 10 g of E51 epoxy resin, 2.6212 g of DMP and 2.5365 g of 4,4'-diaminodicyclohexylmethane (PACM) thoroughly and evenly, and then coat it evenly on a resin plate or tinplate with a coating tool. Cur the coating in an oven at 60°C, 80°C, 100°C and 120°C for two hours respectively to obtain a marine antifouling coating.

[0077] Example 10 (1) Pyrrolidone dicarboxylic acid was prepared in the same manner as in Example 1.

[0078] (2) In the same manner as in Example 1, an epoxy resin containing a pyrrolidone structure was prepared.

[0079] (3) 10 g of chloroacetic acid, 50 g of epoxy resin containing pyrrolidone structure, and 0.06 g of p-toluenesulfonic acid catalyst were heated to 100°C under a nitrogen atmosphere and stirred in an oil bath for 24 hours. After the reaction was completed, chloroacetic acid modified epoxy resin precursor was obtained.

[0080] (4) Mix 10 g of chloroacetic acid modified epoxy resin precursor with 10 g of E51 epoxy resin, 2.6212 g of DMP and 2.5365 g of 4,4'-diaminodicyclohexylmethane (PACM) thoroughly and evenly, and then coat it evenly on a resin plate or tinplate with a coating tool. Cur the coating in an oven at 60°C, 80°C, 100°C and 120°C for two hours respectively to obtain a marine antifouling coating.

[0081] Comparative Example 1 6 g of the pyrrolidone-containing epoxy resin obtained in Example 1 and 14 g of E51 epoxy resin were mixed with 1.1354 g of 4,4'-diaminodicyclohexylmethane (PACM) and then evenly coated onto a resin plate or tinplate using a coating applicator. The mixture was then cured in an oven at 60°C and 80°C for two hours, respectively, to obtain coating 1. Figure 1 Comparative Example 1 at 1710 cm -1 The presence of the OC=O absorption band at this point proves that the epoxy group reacts with the carboxyl group to form an ester bond. Additionally, at 852 cm⁻¹... -1 The weakening of the characteristic absorption band of the nearby epoxy group and 3500 cm -1The enhanced hydroxyl absorption band indicates the occurrence of ring-opening reaction of the epoxy group, which explains the synthesis of pyrrolidone epoxy resin.

[0082] Comparative Example 2 10 g of ethylene glycol glycidyl ether and 3.1256 g of 4,4'-diaminodicyclohexylmethane (PACM) were mixed thoroughly and evenly, and then coated evenly onto a resin board or tinplate using a coating applicator. The mixture was cured in an oven at 60 °C and 80 °C for two hours respectively to obtain coating 2. Figure 1 Comparative Example 2 at 1710 cm -1 There is no absorption peak at 852 cm⁻¹, and at 852 cm⁻¹... -1 The characteristic absorption bands of the nearby epoxy groups are obvious, indicating that no modification reaction has been carried out.

[0083] Comparative Example 3 (1) Pyrrolidone dicarboxylic acid was prepared in the same manner as in Example 1.

[0084] (2) In the same manner as in Example 1, an epoxy resin containing a pyrrolidone structure was prepared.

[0085] (3) 10 g of chloroacetic acid, 50 g of epoxy resin containing pyrrolidone structure, and 0.65 g of p-toluenesulfonic acid catalyst were heated to 100 °C under a nitrogen atmosphere and stirred in an oil bath for 24 hours. After the reaction was completed, chloroacetic acid modified epoxy resin precursor was obtained.

[0086] (4) 10 g of chloroacetic acid modified epoxy resin precursor, 2.8084 g of DMP and 1.3626 g of 4,4'-diaminodicyclohexylmethane (PACM) were mixed thoroughly and evenly, and then coated evenly on resin plate or tinplate sheet with a coating tool. The coating was cured in an oven at 60℃, 80℃, 100℃ and 120℃ for two hours respectively to obtain coating 3.

[0087] Comparative Example 4 (1) Pyrrolidone dicarboxylic acid was prepared in the same manner as in Example 1.

[0088] (2) In the same manner as in Example 1, an epoxy resin containing a pyrrolidone structure was prepared.

[0089] (3) 10 g of chloroacetic acid, 50 g of epoxy resin containing pyrrolidone structure, and 0.65 g of p-toluenesulfonic acid catalyst were heated to 100°C under a nitrogen atmosphere and stirred in an oil bath for 24 hours. After the reaction was completed, chloroacetic acid modified epoxy resin precursor was obtained.

[0090] (4) 10 g of chloroacetic acid modified epoxy resin precursor, 95 g of E51 epoxy resin, 2.8084 g of DMP and 4.7768 g of 4,4'-diaminodicyclohexylmethane (PACM) were mixed thoroughly and evenly, and then evenly coated onto a resin plate or tinplate using a coating applicator. The coating was cured in an oven at 60°C, 80°C, 100°C and 120°C for two hours respectively to obtain coating 4.

[0091] The coating prepared by coating 4 has an excessively high content of E51 epoxy resin, which basically does not degrade and cannot generate a self-renewing surface in time. It has poor antifouling effect and is not suitable for marine antifouling coatings.

[0092] Sample Analysis I. Surface morphology test The 3D surface morphology of the marine antifouling coating prepared in Example 2 and the coating 2 of Comparative Example 2 before and after degradation was measured using a 3D surface profilometer (UP-Lambda, USA). The measurements were taken using an area scan mode at a depth of 1 × 1.91 mm. 2 The surface morphology of each sample was observed within the designated area. The surface morphology before and after coating immersion was analyzed using a scanning electron microscope Sigma 300 (ZEISS, Germany).

[0093] Figure 3 The figures show a comparison of the morphology of the marine antifouling coating prepared in Example 2 and the coating 2 in Comparative Example 2 before and after immersion in seawater for two weeks. As shown in the figures, the surface of the coating in Example 2 after immersion for two weeks showed a significant change compared to before degradation, indicating that the coating had degraded. The surface of the coating in Comparative Example 2 did not change much before and after immersion, indicating that the coating had not degraded.

[0094] II. Sterilization effect The antifouling performance of the samples in Examples 1-3 and Comparative Examples 1 and 2 was evaluated using colony counting. The bacterial strains used in the experiment included Gram-negative bacteria *Escherichia coli*. E. coli (ATCC8739) and Gram-positive Staphylococcus aureus ( S. aureus (ATCC 6538). Before testing, all instruments and solutions were sterilized in an autoclave, and the test samples were sterilized with alcohol and deionized water. Then, *Escherichia coli*, *Staphylococcus aureus*, or *Vibrio parahaemolyticus* were inoculated into Erlenmeyer flasks containing 75 mL LB broth and incubated at 37 °C and 150 rpm for 18 hours. Then, 45 mL of the culture medium was removed and diluted with phosphate-buffered saline (PBS). The resulting bacterial solution was diluted to 10⁻⁶. 8The concentration of CFU / mL was determined, and then 400 μL of the solution was extracted using a pipette. The coated sample was incubated at 37 ℃ for 24 hours using a patch culture method, followed by mixing with the bacterial solution (10...). 3 The samples (CFU / mL) were inoculated together onto nutrient agar plates and incubated for 24 hours. Antimicrobial testing was performed three times independently for each sample. The obtained images were then processed to calculate the sterilization rate.

[0095] Figure 4 The graph shows the antibacterial rates of Examples 1-3 and Comparative Examples 1 and 2 against Escherichia coli and Staphylococcus aureus. The marine antifouling coatings prepared in Examples 1-3 showed antibacterial rates of over 95% against Escherichia coli and Staphylococcus aureus, while Comparative Example 1 (without chloroacetic acid modification) and Comparative Example 2 (without pyrrolidone structure) showed poorer antibacterial effects.

[0096] The above description is merely a preferred embodiment of the present invention and is not intended to limit the present invention. Although the present invention has been described in detail with reference to the foregoing embodiments, those skilled in the art can still modify the technical solutions described in the foregoing embodiments or make equivalent substitutions for some of the technical features. 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. A chloroacetic acid-modified epoxy resin precursor, characterized in that, The structure of the chloroacetic acid-modified epoxy resin precursor is shown in formula (I) or formula (II): Equation (I) Formula (II) Where n = 1 to 5.

2. The method for preparing the chloroacetic acid-modified epoxy resin precursor according to claim 1, characterized in that, Includes the following steps: (1) After mixing itaconic acid, glycine and water, Michael addition reaction was carried out, followed by washing with organic solvent and filtration to obtain pyrrolidone dicarboxylic acid; (2) After adding ethylene glycol glycidyl ether and accelerator to the pyrrolidone dicarboxylic acid obtained in step (1) for dehydration condensation reaction, epoxy resin containing pyrrolidone structure is obtained. (3) The epoxy resin containing pyrrolidone structure obtained in step (2) is reacted with chloroacetic acid under the action of a catalyst to obtain a chloroacetic acid modified epoxy resin precursor.

3. The method for preparing the chloroacetic acid-modified epoxy resin precursor according to claim 1, characterized in that, In step (3), the molar ratio of chloroacetic acid to epoxy resin containing pyrrolidone structure is 1:3~18.

4. The method for preparing the chloroacetic acid-modified epoxy resin precursor according to claim 1, characterized in that, In step (3), the catalyst is at least one of p-toluenesulfonic acid, methanesulfonic acid, trifluoromethanesulfonic acid, benzenesulfonic acid, p-nitrobenzenesulfonic acid, boron trifluoride, etc.

5. The method for preparing the chloroacetic acid-modified epoxy resin precursor according to claim 1, characterized in that, In step (3), the amount of catalyst added is 1 wt% to 5 wt% of the total mass of epoxy resin containing pyrrolidone structure and chloroacetic acid.

6. A marine antifouling coating, characterized in that, A marine antifouling coating is obtained by subjecting the chloroacetic acid-modified epoxy resin precursor of claim 1 and E51 epoxy resin to a gradient curing reaction under the action of a curing agent.

7. The marine antifouling coating according to claim 6, characterized in that, The mass ratio of the chloroacetic acid-modified epoxy resin precursor to E51 epoxy resin is 1:0.1~6.

8. The marine antifouling coating according to claim 6, characterized in that, The curing agent is a tertiary amine curing agent and an epoxy curing agent; the tertiary amine curing agent is at least one of 2,4,6-tris(dimethylaminomethyl)phenol, 1,1,1-trimethylpropane tri-[3(diethylamine)propionate], benzyl dimethylamine, dimethylaminopropylamine, triethylamine, and N,N-dimethylcyclohexylamine; the epoxy curing agent is at least one of phthalic anhydride, tetrahydrophthalic anhydride, methylhexahydrophthalic anhydride, diethylenetriamine, tetraethylenepentamine, ethylenediamine, hexamethylenediamine, isophorone diamine, 4,4'-diaminodiphenyl sulfone, and 4,4'-diaminodiphenylmethane.

9. The marine antifouling coating according to claim 6, characterized in that, The mass ratio of the curing agent is as follows: the total mass ratio of the chloroacetic acid modified epoxy resin precursor and E51 epoxy resin is 8~54:100, wherein the mass ratio of the tertiary amine curing agent to the epoxy curing agent is 1~5:1~8.

10. The marine antifouling coating according to any one of claims 6 to 9, characterized in that, The marine antifouling coating has intrinsic bactericidal effect, and the bactericidal rate of the marine antifouling coating against Staphylococcus aureus and Escherichia coli is ≥95%.

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