Water-based environment-friendly coating and preparation method thereof

Abstract

This invention belongs to the field of coating technology, specifically relating to a water-based environmentally friendly coating and its preparation method. The water-based environmentally friendly coating comprises the following raw materials in parts by weight: 60-70 parts of organosilicon-modified polyurethane emulsion, 3-5 parts of functional additives, 8-12 parts of nano-silica dispersion, 0.1-0.5 parts of defoamer, 0.2-0.8 parts of leveling agent, 1-3 parts of silane coupling agent, 2-5 parts of film-forming aid, and 10-20 parts of deionized water. The functional additives added to the water-based environmentally friendly coating of this invention contain three highly active heterocyclic compounds—pyrazole, benzimidazole, and triazole—as well as thioether bonds and bis-quaternary ammonium cation centers, constructing a multifunctional dicationic anti-corrosion core monomer integrating chemical adsorption, physical barrier, and electrochemical inhibition, thereby improving the coating's anti-corrosion properties. Simultaneously, the functional additives synergistically work with the organosilicon-modified polyurethane emulsion and nano-silica in the coating, further enhancing the coating's water resistance and anti-corrosion properties.

Description

Technical Field

[0001] This invention belongs to the field of coating technology, specifically relating to a water-based environmentally friendly coating and its preparation method. Background Technology

[0002] With the increasing awareness of environmental protection, traditional solvent-based coatings are facing unprecedented challenges and pressure to be replaced due to their high emissions of volatile organic compounds (VOCs), which seriously pollute the environment. Water-based environmentally friendly coatings, which use water as a dispersion medium or diluent, offer advantages such as low VOC emissions, non-flammability and explosion resistance, and safe construction, leading to their widespread application and rapid development in various fields such as building decoration, industrial protection, automobile manufacturing, and electronics.

[0003] However, water-based environmentally friendly coatings still face several pressing technical challenges in practical applications: First, their corrosion resistance is insufficient. Conventional water-based coatings have limited resistance to acid and alkali corrosion and salt spray erosion in harsh environments such as strong acids and alkalis, making it difficult to achieve long-term protection of the substrate. Second, their water resistance is poor. Most water-based coatings use highly hydrophilic additives and dispersants, which, while effectively improving the dispersion stability of pigments and fillers, can easily lead to decreased water resistance and increased water absorption. Furthermore, the high surface tension and poor wettability of water result in poor adhesion between the coating and the substrate, making it prone to blistering and peeling in humid environments. Therefore, in-depth research on the corrosion resistance and water resistance of water-based environmentally friendly coatings, and the development of novel water-based coating systems that combine excellent corrosion resistance and good water resistance, are of great significance and application value for promoting the green and sustainable development of the coating industry. Summary of the Invention

[0004] The primary objective of this invention is to provide a water-based environmentally friendly coating.

[0005] The second objective of this invention is to provide a method for preparing water-based environmentally friendly coatings.

[0006] To achieve the above objectives, the technical solution adopted by the present invention is as follows: This invention provides a water-based environmentally friendly coating, comprising the following raw materials in parts by weight: 60-70 parts of silicone-modified polyurethane emulsion, 3-5 parts of functional additives, 8-12 parts of nano-silica dispersion, 0.1-0.5 parts of defoamer, 0.2-0.8 parts of leveling agent, 1-3 parts of silane coupling agent, 2-5 parts of film-forming aid, and 10-20 parts of deionized water; the chemical structural formula of the functional additives is as follows: .

[0007] Preferably, the preparation method of the functional additive includes the following steps: (1) Add acetylacetone to ethanol, cool to 0-5℃, then add hydrazine hydrate and react at 70-80℃ for 2-3 hours to obtain intermediate 1; (2) Add intermediate 1 and sodium hydroxide to acetonitrile, stir for 0.5-1h, then add 1,2-dibromoethane, and react at 50-60℃ for 5-6h to obtain intermediate 2; (3) Add 2-mercaptobenzimidazole and potassium carbonate to DMF, then add intermediate 2, and react at 80-90℃ for 4-5 h to obtain intermediate 3; (4) Add intermediate 3 and 3-amino-1,2,4-triazole to ethanol, then add formaldehyde solution, and react at 75-85℃ for 6-8h to obtain intermediate 4; (5) Add intermediate 4 to acetonitrile, then add p-nitrobromoacetophenone, and react at 80-85℃ for 12-16h to obtain the functional additive.

[0008] Preferably, in step (1), the ratio of acetylacetone, ethanol and hydrazine hydrate is 1 mol: 300-400 mL: 1.0-1.1 mol.

[0009] Preferably, in step (2), the ratio of intermediate 1, sodium hydroxide, acetonitrile, and 1,2-dibromoethane is 1 mol: 1.2-1.5 mol: 500-600 mL: 2.0-3.0 mol.

[0010] Preferably, in step (3), the ratio of 2-mercaptobenzimidazole, potassium carbonate, DMF and intermediate 2 is 1 mol: 1.2-1.5 mol: 400-500 mL: 1.0-1.1 mol.

[0011] Preferably, in step (4), the ratio of intermediate 3, 3-amino-1,2,4-triazole, ethanol, and formaldehyde solution is 1 mol: 1 mol: 600-800 mL: 1.2-1.5 mol; and the concentration of the formaldehyde solution is 35-40 wt%.

[0012] Preferably, in step (5), the ratio of intermediate 4, acetonitrile, and p-nitrobromoacetophenone is 1 mol: 800-1000 mL: 2.2-2.5 mol.

[0013] Preferably, the solid content of the nano-silica dispersion is 20-30%, and the particle size is 10-20 nm.

[0014] Preferably, the defoamer is an organosilicone defoamer; the leveling agent is an organosilicone leveling agent; the silane coupling agent is KH-560; and the film-forming aid is alcohol ester-12.

[0015] The present invention provides a method for preparing the water-based environmentally friendly coating, the method comprising the following steps: weighing each raw material component according to the ratio, mixing and stirring each raw material component evenly to obtain the coating.

[0016] Compared with the prior art, the main advantages of the present invention are as follows: This invention provides a water-based environmentally friendly coating in which the functional additives integrate three highly active heterocyclic compounds—pyrazole, benzimidazole, and triazole—into a single molecular chain, while simultaneously introducing thioether bonds and a dual-quaternary ammonium cation center. The aim is to utilize the multi-atom synergistic effect to form a super-strong coordination adsorption layer on the metal surface. The Mannich reaction is used to achieve flexible linkage between different heterocyclic compounds, and the reaction of nitrobromoacetophenone with the heterocyclic nitrogen atom achieves dual-site ionization, thereby constructing a multifunctional dual-cationic anti-corrosion core monomer integrating chemical adsorption, physical barrier, and electrochemical inhibition. Furthermore, the organosilicon-modified polyurethane emulsion in this water-based environmentally friendly coating provides a low surface energy hydrophobic barrier, and nano-silica constructs a physical shielding network. These components, along with the functional additives, synergistically enhance the coating's water resistance and corrosion resistance. Simultaneously, the dual-quaternary ammonium cation structure of the functional additives enhances electrostatic adsorption with the metal substrate, and its interaction with the silane coupling agent improves the bonding strength between the coating film and the metal substrate. This water-based environmentally friendly coating achieves highly efficient and long-lasting comprehensive protective performance under harsh environments while ensuring its environmental friendliness. Detailed Implementation

[0017] The technical solution of the present invention will be further described below with reference to specific embodiments. However, those skilled in the art should understand that the following embodiments are only for illustrating the present invention and should not be regarded as limiting the present invention. Specific conditions not specified in the embodiments are performed according to conventional conditions or conditions recommended by the manufacturer. Unless otherwise specified, the reagents or instruments used are all conventional products obtained through commercial channels.

[0018] Example 1 This embodiment provides a water-based environmentally friendly coating, comprising the following raw materials in parts by weight: silicone-modified polyurethane emulsion (SILIKOPUR). ® 65 parts of 8081), 4 parts of functional additives, 10 parts of nano-silica dispersion (solid content 20-30%, particle size 10-20nm), 0.3 parts of defoamer (organosilicone defoamer, BYK028), and 0.3 parts of leveling agent (organosilicone leveling agent, TEGO). ® 0.6 parts of Glide410, 2 parts of silane coupling agent (KH-560), 3 parts of film-forming aid (alcohol ester-12), and 15 parts of deionized water.

[0019] The preparation method of the functional additive in this embodiment includes the following steps: (1) Acetylacetone was added to ethanol, cooled to 0°C, and hydrazine hydrate was added dropwise, keeping the temperature below 15°C during the addition process; the ratio of acetylacetone, ethanol, and hydrazine hydrate was 1 mol: 350 mL: 1.1 mol; after the addition was complete, the mixture was heated to 75°C and stirred under reflux for 2.5 h; after the reaction was completed, ethanol was removed under reduced pressure, the residue was poured into ice water and stirred thoroughly, a solid was precipitated, filtered, the filter cake was washed with cold water, and dried under vacuum to obtain intermediate 1 with a yield of 95.5%; intermediate 1 1 HNMR: (C5H8N2, 400MHz, DMSO- d6 ) δ: 2.12 (s, 6H), 5.73 (s, 1H), 11.92 (s, 1H). HRMS (ESI) m / z=96.07[M].

[0020] (2) Intermediate 1 and sodium hydroxide were added to acetonitrile, and after stirring for 1 h, 1,2-dibromoethane was added. The ratio of intermediate 1, sodium hydroxide, acetonitrile, and 1,2-dibromoethane was 1 mol: 1.4 mol: 550 mL: 2.5 mol. The mixture was heated to 55 °C and reacted for 5.5 h. After cooling, the reaction solution was filtered, and the filtrate was concentrated under reduced pressure. The residue was added to dichloromethane, washed successively with water and saturated brine, dried over anhydrous magnesium sulfate, and the solvent was removed under reduced pressure. Intermediate 2 was obtained by column chromatography with a yield of 88.0%. 1 HNMR: (C7H) 11 BrN2, 400MHz, DMSO- d6 ) δ: 2.30 (s, 3H), 2.41 (s, 3H), 3.78 (t, 2H), 4.23 (t, 2H), 6.16 (s, 1H). HRMS (ESI) m / z=202.01[M].

[0021] (3) Add 2-mercaptobenzimidazole and potassium carbonate to DMF (N,N-dimethylformamide), and add intermediate 2. The ratio of 2-mercaptobenzimidazole, potassium carbonate, DMF, and intermediate 2 is 1 mol: 1.4 mol: 450 mL: 1.1 mol. Heat to 85 °C and stir for 4.5 h. After cooling the reaction solution, pour it into ice water, stir to precipitate the solid, filter, wash the filter cake with water, recrystallize with ethanol / water, and dry to obtain intermediate 3 with a yield of 90.5%. 1 HNMR: (C 14 H 16 N4S, 400MHz, DMSO- d6) δ: 2.30 (s, 3H), 2.41 (s, 3H), 3.41 (t, 2H), 4.13 (t, 2H), 6.16 (s, 1H), 7.13 (m, 2H), 7.44 (m, 2H), 12.55 (s, 1H). HRMS (ESI) m / z=273.11[M+H] + .

[0022] (4) Intermediate 3 and 3-amino-1,2,4-triazole were added to ethanol, and formaldehyde solution (37 wt%) was added. The ratio of intermediate 3, 3-amino-1,2,4-triazole, ethanol, and formaldehyde solution was 1 mol: 1 mol: 700 mL: 1.4 mol. The mixture was heated to 80 °C and refluxed for 7 h. The reaction solution was concentrated under reduced pressure to half its volume, cooled to precipitate a solid, filtered, and the filter cake was washed with cold ethanol and dried under vacuum to obtain intermediate 4, with a yield of 86.5%. 1 HNMR: (C 17 H 20 N8S, 400MHz, DMSO- d6 ) δ: 2.30 (s, 3H), 2.41 (s, 3H), 3.41 (t, 2H), 4.13 (t, 2H), 5.68 (s, 2H), 5.95 (s, 1H) ), 6.16 (s, 1H), 7.18-7.27 (m, 2H), 7.52 (m, 1H), 7.62-7.64 (m, 2H), 9.61 (s, 1H). HRMS (ESI) m / z=369.16[M+H] + .

[0023] (5) Add intermediate 4 to acetonitrile, then add p-nitrobromoacetophenone, wherein the ratio of intermediate 4, acetonitrile, and p-nitrobromoacetophenone is 1 mol: 900 mL: 2.4 mol; heat to 85 °C and reflux for 14 h; a large amount of solid precipitates during the reaction. After the reaction is complete, cool to room temperature, filter, and wash the filter cake three times with cold acetonitrile and anhydrous diethyl ether, and then dry under vacuum to obtain the final product (functional additive), with a yield of 82.0%; the functional additive 1 HNMR: (C 33 H 32 Br2N 10 O6S, 400MHz, DMSO- d6) δ: 2.42 (s, 3H), 2.49 (s, 2H), 2.91 (s, 3H), 3.41 (t, 2H), 4.13 (t, 2H), 5.68 (s, 2H), 5.95 (s, 1H), 6.16 (s, 1H), 6.29 (s, 2H), 7.39 (m, 1H), 7.62 (s, 1H), 7.72 (m, 1H), 8.23 ​​(m, 1H), 8.31 (m, 4H), 8.40 (m, 4H), 8.60 (m, 1H), 9.61 (s, 1H). HRMS (ESI) m / z=348.11[M-2Br] 2+ / 2.

[0024] This embodiment provides a method for preparing a water-based environmentally friendly coating, including the following steps: weighing each raw material component according to the ratio, mixing and stirring each raw material component evenly, and then obtaining the coating.

[0025] Example 2 This embodiment provides a water-based environmentally friendly coating, comprising the following raw materials in parts by weight: silicone-modified polyurethane emulsion (SILIKOPUR). ® 70 parts of 8081, 5 parts of functional additives, 12 parts of nano-silica dispersion (solid content 20-30%, particle size 10-20nm), 0.5 parts of defoamer (organosilicone defoamer, BYK028), and 0.5 parts of leveling agent (organosilicone leveling agent, TEGO). ® 0.8 parts of Glide410, 3 parts of silane coupling agent (KH-560), 5 parts of film-forming aid (alcohol ester-12), and 20 parts of deionized water.

[0026] The preparation method of the functional additive in this embodiment includes the following steps: (1) Acetylacetone was added to ethanol, cooled to 5°C, and hydrazine hydrate was added dropwise, keeping the temperature below 15°C during the addition process; the ratio of acetylacetone, ethanol, and hydrazine hydrate was 1 mol: 400 mL: 1.1 mol; after the addition was complete, the mixture was heated to 80°C and stirred under reflux for 2 h; after the reaction was completed, ethanol was removed under reduced pressure, the residue was poured into ice water and stirred thoroughly, a solid was precipitated, filtered, the filter cake was washed with cold water, and dried under vacuum to obtain intermediate 1, with a yield of 94.7%; intermediate 1 1 HNMR is the same as in Example 1.

[0027] (2) Intermediate 1 and sodium hydroxide were added to acetonitrile, and after stirring for 1 h, 1,2-dibromoethane was added. The ratio of intermediate 1, sodium hydroxide, acetonitrile, and 1,2-dibromoethane was 1 mol: 1.5 mol: 600 mL: 3.0 mol. The mixture was heated to 60 °C and reacted for 5 h. After cooling, the reaction solution was filtered, and the filtrate was concentrated under reduced pressure. The residue was added to dichloromethane, washed successively with water and saturated brine, dried over anhydrous magnesium sulfate, and the solvent was removed under reduced pressure. Intermediate 2 was obtained by column chromatography with a yield of 87.5%. 1 HNMR is the same as in Example 1.

[0028] (3) Add 2-mercaptobenzimidazole and potassium carbonate to DMF (N,N-dimethylformamide), and add intermediate 2. The ratio of 2-mercaptobenzimidazole, potassium carbonate, DMF, and intermediate 2 is 1 mol: 1.5 mol: 500 mL: 1.1 mol. Heat to 90 °C and stir for 4 h. After cooling the reaction solution, pour it into ice water, stir to precipitate the solid, filter, wash the filter cake with water, recrystallize with ethanol / water, and dry to obtain intermediate 3 with a yield of 88.3%. 1 HNMR is the same as in Example 1.

[0029] (4) Intermediate 3 and 3-amino-1,2,4-triazole were added to ethanol, and formaldehyde solution (37 wt%) was added. The ratio of intermediate 3, 3-amino-1,2,4-triazole, ethanol, and formaldehyde solution was 1 mol: 1 mol: 800 mL: 1.5 mol. The mixture was heated to 85 °C and refluxed for 6 h. The reaction solution was concentrated under reduced pressure to half its volume, cooled to precipitate a solid, filtered, and the filter cake was washed with cold ethanol and dried under vacuum to obtain intermediate 4, with a yield of 85.1%. 1 HNMR is the same as in Example 1.

[0030] (5) Add intermediate 4 to acetonitrile, then add p-nitrobromoacetophenone, wherein the ratio of intermediate 4, acetonitrile, and p-nitrobromoacetophenone is 1 mol: 1000 mL: 2.5 mol; heat to 85 °C and reflux for 12 h; a large amount of solid precipitates during the reaction. After the reaction is complete, cool to room temperature, filter, and wash the filter cake three times with cold acetonitrile and anhydrous diethyl ether, then vacuum dry to obtain the functional additive with a yield of 81.6%; the functional additive... 1 HNMR is the same as in Example 1.

[0031] The preparation method of the water-based environmentally friendly coating in this embodiment is the same as that in Embodiment 1.

[0032] Example 3 This embodiment provides a water-based environmentally friendly coating, comprising the following raw materials in parts by weight: silicone-modified polyurethane emulsion (SILIKOPUR). ®60 parts of 8081), 3 parts of functional additives, 8 parts of nano-silica dispersion (solid content 20-30%, particle size 10-20nm), 0.1 parts of defoamer (organosilicone defoamer, BYK028), and 0.1 parts of leveling agent (organosilicone leveling agent, TEGO). ® 0.2 parts of Glide410, 1 part of silane coupling agent (KH-560), 2 parts of film-forming aid (alcohol ester-12), and 10 parts of deionized water.

[0033] The preparation method of the functional additive in this embodiment includes the following steps: (1) Acetylacetone was added to ethanol, cooled to 0°C, and hydrazine hydrate was added dropwise, keeping the temperature below 15°C during the addition process; the ratio of acetylacetone, ethanol, and hydrazine hydrate was 1 mol: 300 mL: 1.0 mol; after the addition was complete, the mixture was heated to 70°C and stirred under reflux for 3 h; after the reaction was completed, the ethanol was removed under reduced pressure, the residue was poured into ice water and stirred thoroughly, a solid was precipitated, filtered, the filter cake was washed with cold water, and dried under vacuum to obtain intermediate 1, with a yield of 93.8%; intermediate 1 1 HNMR is the same as in Example 1.

[0034] (2) Intermediate 1 and sodium hydroxide were added to acetonitrile, and after stirring for 0.5 h, 1,2-dibromoethane was added. The ratio of intermediate 1, sodium hydroxide, acetonitrile, and 1,2-dibromoethane was 1 mol: 1.2 mol: 500 mL: 2.0 mol. The mixture was heated to 50 °C and reacted for 6 h. After cooling, the reaction solution was filtered, and the filtrate was concentrated under reduced pressure. The residue was added to dichloromethane, washed successively with water and saturated brine, dried over anhydrous magnesium sulfate, and the solvent was removed under reduced pressure. Intermediate 2 was obtained by column chromatography with a yield of 86.4%. 1 HNMR is the same as in Example 1.

[0035] (3) Add 2-mercaptobenzimidazole and potassium carbonate to DMF (N,N-dimethylformamide), and add intermediate 2. The ratio of 2-mercaptobenzimidazole, potassium carbonate, DMF, and intermediate 2 is 1 mol: 1.2 mol: 400 mL: 1.0 mol. Heat to 80 °C and stir for 5 h. After cooling the reaction solution, pour it into ice water, stir to precipitate the solid, filter, wash the filter cake with water, recrystallize with ethanol / water, and dry to obtain intermediate 3 with a yield of 87.2%. 1 HNMR is the same as in Example 1.

[0036] (4) Intermediate 3 and 3-amino-1,2,4-triazole were added to ethanol, and formaldehyde solution (37 wt%) was added. The ratio of intermediate 3, 3-amino-1,2,4-triazole, ethanol, and formaldehyde solution was 1 mol: 1 mol: 600 mL: 1.2 mol. The mixture was heated to 75 °C and refluxed for 8 h. The reaction solution was concentrated under reduced pressure to half its volume, cooled to precipitate a solid, filtered, and the filter cake was washed with cold ethanol and dried under vacuum to obtain intermediate 4, with a yield of 84.9%. 1 HNMR is the same as in Example 1.

[0037] (5) Add intermediate 4 to acetonitrile, then add p-nitrobromoacetophenone, wherein the ratio of intermediate 4, acetonitrile, and p-nitrobromoacetophenone is 1 mol: 800 mL: 2.2 mol; heat to 80 °C and reflux for 16 h; a large amount of solid precipitates during the reaction. After the reaction is complete, cool to room temperature, filter, and wash the filter cake three times with cold acetonitrile and anhydrous diethyl ether, and then vacuum dry to obtain the functional additive with a yield of 80.7%; the functional additive... 1 HNMR is the same as in Example 1.

[0038] The preparation method of the water-based environmentally friendly coating in this embodiment is the same as that in Embodiment 1.

[0039] Comparative Example 1 The difference between this comparative example and Example 1 is that the functional additive in the water-based environmentally friendly coating raw material composition is replaced with intermediate 4, while the rest is the same as in Example 1.

[0040] Comparative Example 2 The difference between this comparative example and Example 1 is that the functional additives in the raw material composition of the water-based environmentally friendly coating are omitted; otherwise, they are the same as in Example 1.

[0041] Test case The coatings obtained in Examples 1-3 and Comparative Examples 1-2 were uniformly applied to the surface of steel. The adhesion, water resistance, acid resistance, alkali resistance, and neutral salt spray resistance of the coatings were tested according to relevant standards. Specifically, adhesion was tested according to GB / T9286-2021 "Cross-cut test for paints and varnishes"; water resistance was tested according to GB / T1733-1993 "Determination of water resistance of paint films"; acid and alkali resistance were tested according to GB / T9274-1988 "Determination of resistance to liquid media for paints and varnishes"; and neutral salt spray resistance was tested according to GB / T1771-2007 "Determination of neutral salt spray resistance for paints and varnishes". The results are shown in Table 1.

[0042] Table 1 As shown in Table 1, the coatings obtained in Examples 1-3 of this invention exhibit better adhesion, water resistance, acid resistance, alkali resistance, and neutral salt spray resistance compared to Comparative Examples 1-2. The reason for this is that the functional additives added to the water-based environmentally friendly coatings of this invention contain three highly active heterocyclic compounds—pyrazole, benzimidazole, and triazole—along with thioether bonds and quaternary ammonium cation centers, constructing a multifunctional dicationic anti-corrosion core monomer that integrates chemical adsorption, physical barrier, and electrochemical inhibition, thereby enhancing the coating's anti-corrosion properties. Simultaneously, the functional additives synergistically work with the organosilicon-modified polyurethane emulsion and nano-silica in the coating, further improving the coating's water resistance and anti-corrosion properties.

[0043] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention, and not to limit them. The basic principles and main features of the present invention have been described above with specific implementation schemes. Based on the present invention, some modifications or substitutions can be made, but these modifications or substitutions do not cause the essence of the corresponding technical solutions to deviate from the scope of protection claimed by the present invention.

Claims

1. An aqueous environmental friendly coating characterized in that, The raw materials include the following parts by weight: 60-70 parts of silicone-modified polyurethane emulsion, 3-5 parts of functional additives, 8-12 parts of nano-silica dispersion, 0.1-0.5 parts of defoamer, 0.2-0.8 parts of leveling agent, 1-3 parts of silane coupling agent, 2-5 parts of film-forming aid, and 10-20 parts of deionized water; the chemical structural formula of the functional additives is as follows: 。 2. The waterborne, environmentally friendly coating of claim 1, wherein, The preparation method of the functional additive includes the following steps: (1) Add acetylacetone to ethanol, cool to 0-5℃, then add hydrazine hydrate and react at 70-80℃ for 2-3 hours to obtain intermediate 1; (2) Add intermediate 1 and sodium hydroxide to acetonitrile, stir for 0.5-1h, then add 1,2-dibromoethane, and react at 50-60℃ for 5-6h to obtain intermediate 2; (3) Add 2-mercaptobenzimidazole and potassium carbonate to DMF, then add intermediate 2, and react at 80-90℃ for 4-5 h to obtain intermediate 3; (4) Add intermediate 3 and 3-amino-1,2,4-triazole to ethanol, then add formaldehyde solution, and react at 75-85℃ for 6-8h to obtain intermediate 4; (5) Add intermediate 4 to acetonitrile, then add p-nitrobromoacetophenone, and react at 80-85℃ for 12-16h to obtain the functional additive.

3. The waterborne, environmentally friendly coating of claim 2, wherein, In step (1), the ratio of acetylacetone, ethanol and hydrazine hydrate is 1 mol: 300-400 mL: 1.0-1.1 mol.

4. The waterborne, environmentally friendly coating of claim 2, wherein, In step (2), the ratio of intermediate 1, sodium hydroxide, acetonitrile, and 1,2-dibromoethane is 1 mol: 1.2-1.5 mol: 500-600 mL: 2.0-3.0 mol.

5. The waterborne, environmentally friendly coating of claim 2, wherein, In step (3), the ratio of 2-mercaptobenzimidazole, potassium carbonate, DMF and intermediate 2 is 1 mol: 1.2-1.5 mol: 400-500 mL: 1.0-1.1 mol.

6. The water-based environmentally friendly coating according to claim 2, characterized in that, In step (4), the ratio of intermediate 3, 3-amino-1,2,4-triazole, ethanol, and formaldehyde solution is 1 mol: 1 mol: 600-800 mL: 1.2-1.5 mol; the concentration of the formaldehyde solution is 35-40 wt%.

7. The water-based environmentally friendly coating according to claim 2, characterized in that, In step (5), the ratio of intermediate 4, acetonitrile, and p-nitrobromoacetophenone is 1 mol: 800-1000 mL: 2.2-2.5 mol.

8. The water-based environmentally friendly coating according to claim 1, characterized in that, The solid content of the nano-silica dispersion is 20-30%, and the particle size is 10-20 nm.

9. The water-based environmentally friendly coating according to claim 1, characterized in that, The defoamer is an organosilicone defoamer; the leveling agent is an organosilicone leveling agent; the silane coupling agent is KH-560; and the film-forming aid is alcohol ester-12.

10. The method for preparing water-based environmentally friendly coatings according to any one of claims 1-9, characterized in that, The preparation method includes the following steps: weigh each raw material component according to the ratio, mix and stir each raw material component evenly, and then obtain the final product.

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