Modified epoxy resin spray paint and preparation method thereof

Abstract

The invention relates to the technical field of coatings, and particularly discloses a modified epoxy resin spray paint and a preparation method thereof. The invention relates to a modified epoxy resin spray paint, which is prepared from 20 to 25 parts of modified epoxy resin emulsion, 10 to 20 parts of caprolactone acrylate, 15 to 25 parts of pigment paste, 30 to 40 parts of solvent, 30 to 35 parts of dimethyl ether, 0.1 to 0.5 part of nano hydroxyapatite, 0.1 to 0.5 part of water-based bentonite and 0.5 to 1 part of dimethyl silicone oil. The preparation of the modified epoxy resin emulsion comprises the following steps: mixing epoxy resin and propylene glycol monomethyl ether, then adding acetone and an initiator, and then dropwise adding acrylic acid, methacrylic acid, hydroxypropyl acrylate and butyl acrylate; and finally, adding triethylamine and deionized water until the solid content reaches 50-60% to obtain the modified epoxy resin emulsion. The modified epoxy resin spray paint provided by the invention has good corrosion resistance, wear resistance and adhesive force, and can meet the comprehensive performance requirements of modern electronic products on a paint layer.

Description

Technical Field

[0001] The invention relates to the technical field of coatings, in particular to a modified epoxy resin spray paint and a preparation method thereof. Background Art

[0002] With the rapid development of modern electronic technology, electronic products such as mobile phones have become an indispensable part of people's daily lives. These products are not only required to have excellent performance, but also must meet consumers' expectations in terms of appearance design and durability. As an important part of the appearance of electronic products, the paint layer not only affects the beauty of the product, but is also directly related to the durability and protection performance of the product.

[0003] Although traditional epoxy resin spray paint can meet the basic requirements of electronic products for paint layers to a certain extent, it still has the problem of poor corrosion resistance. It is easily corroded by environmental factors during long-term use, causing the paint layer to fall off or discolor, thus affecting the overall aesthetics and service life of the product. In response to the above problems, a variety of modified epoxy resin spray paints have been developed in recent years to improve the corrosion resistance of spray paints. However, when these spray paints are applied to electronic products such as mobile phones, although the corrosion resistance is improved, there are still deficiencies in wear resistance and adhesion, and they cannot fully meet the comprehensive performance requirements of modern electronic products for paint layers.

[0004] In view of the shortcomings of the prior art, it is necessary to provide an electronic product spray paint with good comprehensive performance. Summary of the invention

[0005] In order to provide an electronic product spray paint with good comprehensive performance, the present application provides a modified epoxy resin spray paint and a preparation method thereof. The present application found in the research that the comprehensive performance of the epoxy resin spray paint can be significantly improved through specific modification means and formula optimization. The modified epoxy resin spray paint of the present application not only has excellent corrosion resistance, but also has good wear resistance and adhesion, and can meet the comprehensive performance requirements of modern electronic products for the paint layer.

[0006] In the first aspect, the modified epoxy resin spray paint provided in the present application adopts the following technical solution: A modified epoxy resin spray paint comprises the following components in parts by mass: 20-25 parts of modified epoxy resin emulsion, 10-20 parts of caprolactone acrylate, 15-25 parts of pigment slurry, 30-40 parts of solvent, 30-35 parts of dimethyl ether, 0.1-0.5 parts of nano-hydroxyapatite, 0.1-0.5 parts of water-based bentonite, and 0.5-1 parts of dimethyl silicone oil; The preparation of the modified epoxy resin emulsion comprises the following steps: Step 1: Under a nitrogen atmosphere, take 10 parts of epoxy resin, add 11-12 parts of propylene glycol methyl ether, and heat to 60°C while stirring until the epoxy resin is completely dissolved, then add 1-2 parts of acetone and 0.02-0.03 parts of initiator, and keep warm for 30 minutes; Step 2: Heat the solution obtained in step 1 to 80°C, and then drop a mixed solution consisting of 0.03-0.04 parts of initiator, 2-3 parts of acrylic acid, 1-2 parts of methacrylic acid, 0.5-1 parts of hydroxypropyl acrylate, and 5-8 parts of butyl acrylate, and complete the dropwise addition within 1.5 hours, and keep warm for 2-3 hours; Step 3: Triethylamine is added dropwise to the solution obtained in step 2 until the pH value is 8-9; Step 4: Slowly add deionized water to the solution obtained in step 3 to make the solid content reach 50%-60%, and then centrifuge until it is evenly dispersed to obtain a modified epoxy resin emulsion.

[0007] In the above technical scheme, the present application not only improves the corrosion resistance of epoxy resin spray paint, but also significantly enhances its wear resistance and adhesion through specific modification means and formula optimization. Specifically, the present application can further enhance the wear resistance and corrosion resistance of the paint layer by introducing modified epoxy resin and caprolactone acrylate, making the paint layer less prone to wear during long-term use, and improving the protective effect of the paint layer on the substrate. At the same time, the addition of pigment slurry not only gives the spray paint good hiding power and color performance, but also enhances the adhesion of the paint layer by optimizing the compatibility of the pigment and the resin.

[0008] Furthermore, the present application modifies the epoxy resin by using acrylic acid, methacrylic acid, and hydroxypropyl acrylate, and introduces active groups into the epoxy resin, thereby increasing the crosslinking density of the paint layer, which can effectively improve the impact resistance and adhesion of the paint layer, and enhance the adhesion of the paint layer on different substrates.

[0009] Furthermore, the present application can effectively improve the adhesion, corrosion resistance and impact resistance of the paint layer by introducing nano-hydroxyapatite, water-based bentonite and dimethyl silicone oil. Nano-hydroxyapatite has good biocompatibility and chemical stability, and can form a stable composite material with epoxy resin, thereby improving the mechanical properties and chemical corrosion resistance of the paint layer. Water-based bentonite has good dispersibility and adsorption, which can further enhance the adhesion and water resistance of the paint layer. Dimethyl silicone oil can form a protective film on the surface of the paint layer, effectively preventing the intrusion of moisture and pollutants, thereby improving the durability and protective performance of the paint layer.

[0010] Preferably, the epoxy resin includes at least epoxy resin E-51.

[0011] In the above technical solution, the present application further optimizes the performance of the paint layer by modifying the epoxy resin E-51. Epoxy resin E-51 is a commonly used bisphenol A type epoxy resin with good comprehensive properties, such as excellent adhesion, chemical corrosion resistance and electrical insulation. By modifying it, the comprehensive performance of the paint layer can be further improved to meet the higher requirements of electronic products for the paint layer.

[0012] Preferably, the epoxy resin is a mixture of epoxy resin E-51 and prefabricated epoxy resin, the mass ratio of the epoxy resin E-51 to the prefabricated epoxy resin is 1:(1-2), and the preparation method of the prefabricated epoxy resin comprises: Step 1: Under a nitrogen atmosphere, mix 10 parts of epoxy resin E-51, 3-5 parts of styrene sulfonic acid, 4-6 parts of erucic acid, and 2-3 parts of isooleic acid, stir and heat to 100-120°C, and maintain the temperature for 2 hours; Step 2: After uniformly mixing 0.01-0.02 parts of N, N-dimethylethanolamine and 1.5-2 parts of propylene glycol methyl ether, add dropwise to the solution obtained in step 1, and complete the addition within 30 minutes. Continue to react until the acid value is less than 3 mgKOH / g to obtain a prefabricated epoxy resin.

[0013] In the above technical scheme, the present application further improves the comprehensive performance of the paint layer by modifying the epoxy resin E-51 and the prefabricated epoxy resin, especially by modifying the prefabricated epoxy resin. The preparation method of the prefabricated epoxy resin introduces styrene sulfonic acid, erucic acid and isooleic acid, so that the epoxy resin can better combine with the active group during the modification process, thereby improving the crosslinking density and chemical corrosion resistance of the paint layer.

[0014] Preferably, the pigment slurry comprises the following components, based on the mass fraction of the pigment slurry: 60-70 parts of modified epoxy resin emulsion, 15-25 parts of pigment, 25-35 parts of solvent, and 1-2 parts of wetting and dispersing agent.

[0015] In the above technical solution, the present application further optimizes the performance of spray painting by selecting a specific pigment slurry formula. The modified epoxy resin emulsion contained in the pigment slurry can be fully mixed with the pigment to ensure uniform distribution of the pigment in the paint layer, thereby providing better color uniformity and hiding power. At the same time, the addition of a wetting dispersant helps disperse the pigment particles in the resin, prevents the pigment from agglomerating, and ensures a smooth and beautiful surface of the paint layer.

[0016] Preferably, the method for preparing the pigment slurry comprises: taking modified epoxy resin emulsion, pigment, solvent and wetting dispersant according to the formula, then mixing them evenly at 1000-1500 rpm, and then grinding them to a fineness of less than 15 μm to obtain the pigment slurry.

[0017] In the above technical scheme, the present application ensures the dispersibility and stability of the pigment slurry by optimizing the preparation method of the pigment slurry. Through high-speed mixing and grinding, the pigment particles are fully dispersed and evenly distributed in the modified epoxy resin emulsion. By controlling the fineness to below 15μm, it can be ensured that the surface after painting has good smoothness and color uniformity, while avoiding possible color difference and granularity.

[0018] Preferably, the solvent is a combination of ethyl acetate, n-butanol and acetone, which comprises 10-15 parts of ethyl acetate, 15-20 parts of n-butanol and 0-5 parts of acetone based on the mass fraction of the modified epoxy resin spray paint.

[0019] In the above technical scheme, the present application further optimizes the volatility and solubility of the spray paint by limiting the solvent to a combination of ethyl acetate, n-butanol, and acetone. The combination of ethyl acetate, n-butanol, and acetone can provide good dissolving power, ensuring that the modified epoxy resin emulsion can be evenly dispersed during the spray painting process, while ensuring that the volatilization rate of the spray paint is moderate, avoiding paint surface defects caused by too fast solvent volatilization. In addition, this solvent combination also has low toxicity, meets environmental protection requirements, and is beneficial to the health of operators and environmental protection.

[0020] Preferably, the initiator is benzoyl peroxide.

[0021] In the above technical solution, benzoyl peroxide is a commonly used initiator, which can initiate free radical polymerization at a relatively low temperature, thereby effectively promoting the formation of modified epoxy resin emulsion. It has high initiation efficiency and mild reaction conditions, which is conducive to controlling the reaction process and ensuring the stable quality of the spray paint product.

[0022] In the second aspect, the present application provides a method for preparing a modified epoxy resin spray paint using the following technical solution: A method for preparing a modified epoxy resin spray paint, comprising: Firstly, the modified epoxy resin emulsion and caprolactone acrylate are uniformly mixed, and then the pigment slurry, solvent, dimethyl ether, nano-hydroxyapatite, water-based bentonite and dimethyl silicone oil are added in sequence, and after uniform mixing, the modified epoxy resin spray paint is obtained.

[0023] In the above technical scheme, the present application obtains a uniform and stable modified epoxy resin spray paint through the above preparation method. Such modified epoxy resin spray paint not only has good corrosion resistance, but also has good adhesion and impact resistance. It can be widely used in various electronic products, such as mobile phones, tablet computers, laptop computers, etc. The shell coating can form a uniform and smooth paint layer on the substrate, and the drying speed is fast, which greatly improves the production efficiency.

[0024] In summary, the present application includes at least one of the following beneficial technical effects: 1. This application significantly improves the corrosion resistance and wear resistance of the paint layer by introducing modified epoxy resin and caprolactone acrylate, making it less prone to wear during long-term use and able to provide good protection for the substrate.

[0025] 2. This application further effectively improves the adhesion, corrosion resistance and impact resistance of the paint layer, and improves the durability and protective performance of the paint layer by introducing three additives: nano-hydroxyapatite, water-based bentonite and dimethyl silicone oil.

[0026] 3. The modified epoxy resin spray paint prepared in this application has good corrosion resistance, adhesion and impact resistance, is suitable for coating of various electronic product shells, and has significant technical advantages and application value. DETAILED DESCRIPTION

[0027] In order to better illustrate the purpose, technical solutions and advantages of the present invention, the present invention will be further described below in conjunction with specific embodiments.

[0028] The sources of raw materials in the following specific implementation methods are shown in Table 1.

[0029] Table 1: Example 1 A modified epoxy resin spray paint comprises: 2kg of modified epoxy resin emulsion, 2kg of caprolactone acrylate, 1.5kg of pigment slurry, 3kg of solvent, 3kg of dimethyl ether, 0.05kg of nano hydroxyapatite, 0.01kg of water-based bentonite and 0.05kg of dimethyl silicone oil.

[0030] The solvent is a mixture of 1 kg ethyl acetate, 1.5 kg n-butanol, and 0.5 kg acetone.

[0031] Wherein, the preparation of modified epoxy resin emulsion comprises the following steps: Step 1: Under a nitrogen atmosphere, take 10 kg of epoxy resin, add 11 kg of propylene glycol methyl ether, and heat to 60°C while stirring until the epoxy resin is completely dissolved. Then add 1 kg of acetone and 0.02 kg of initiator, and keep the reaction warm for 30 minutes.

[0032] Step 2: Heat the solution obtained in step 1 to 80°C, and then dropwise add a mixed solution consisting of 0.04 kg initiator, 2 kg acrylic acid, 2 kg methacrylic acid, 0.5 kg hydroxypropyl acrylate, and 5 kg butyl acrylate. The addition should be completed within 1.5 hours, and the mixture should be kept warm for 2 hours.

[0033] Step 3: Triethylamine was added dropwise to the solution obtained in step 2 until the pH value reached 8.

[0034] Step 4: Slowly add deionized water to the solution obtained in step 3 to make the solid content reach 50%, and then centrifuge until it is evenly dispersed to obtain a modified epoxy resin emulsion.

[0035] Wherein, the initiator is benzoyl peroxide.

[0036] The epoxy resin is a mixture of epoxy resin E-51 and prefabricated epoxy resin in a mass ratio of 1:1.

[0037] Wherein, the preparation method of prefabricated epoxy resin comprises: s1: Under a nitrogen atmosphere, 10 kg of epoxy resin E-51, 3 kg of styrene sulfonic acid, 4 kg of erucic acid, and 3 kg of isooleic acid were mixed, stirred, heated to 100°C, and maintained at this temperature for 2 hours.

[0038] s2: After uniformly mixing 0.02 kg N, N-dimethylethanolamine and 2 kg propylene glycol methyl ether, add dropwise to the solution obtained in step 1 within 30 min, and continue the reaction until the acid value is <3 mg KOH / g to obtain a prefabricated epoxy resin.

[0039] The preparation method of the pigment slurry includes: taking 6 kg of modified epoxy resin emulsion, 1.5 kg of pigment, 1 kg of ethyl acetate, 2 kg of butyl acetate and 0.1 kg of wetting dispersant, then mixing them evenly at 1000 rpm, and then grinding them to a fineness of less than 15 μm to obtain the pigment slurry.

[0040] Example 2 A modified epoxy resin spray paint, which is different from Example 1 in that it includes: 2.5 kg of modified epoxy resin emulsion, 1 kg of caprolactone acrylate, 2.5 kg of pigment slurry, 4 kg of solvent, 3.5 kg of dimethyl ether, 0.01 kg of nano-hydroxyapatite, 0.05 kg of water-based bentonite, and 0.1 kg of dimethyl silicone oil.

[0041] The solvent is a mixture of 1.5 kg ethyl acetate, 2 kg n-butanol, and 0.5 kg acetone.

[0042] Wherein, the preparation of modified epoxy resin emulsion comprises the following steps: Step 1: Under a nitrogen atmosphere, take 10 kg of epoxy resin, add 12 kg of propylene glycol methyl ether, and heat to 60°C while stirring until the epoxy resin is completely dissolved. Then add 2 kg of acetone and 0.03 kg of initiator, and keep the reaction warm for 30 minutes.

[0043] Step 2: Heat the solution obtained in step 1 to 80°C, and then drop a mixed solution consisting of 0.03 kg initiator, 3 kg acrylic acid, 1 kg methacrylic acid, 1 kg hydroxypropyl acrylate, and 8 kg butyl acrylate. The addition should be completed within 1.5 hours, and the mixture should be kept warm for 3 hours.

[0044] Step 3: Triethylamine was added dropwise to the solution obtained in step 2 until the pH value reached 9.

[0045] Step 4: Slowly add deionized water to the solution obtained in step 3 to make the solid content reach 60%, and then centrifuge until it is evenly dispersed to obtain a modified epoxy resin emulsion.

[0046] Wherein, the initiator is benzoyl peroxide.

[0047] The epoxy resin is a mixture of epoxy resin E-51 and prefabricated epoxy resin in a mass ratio of 1:2.

[0048] Wherein, the preparation method of prefabricated epoxy resin comprises: s1: Under a nitrogen atmosphere, 10 kg of epoxy resin E-51, 5 kg of styrene sulfonic acid, 6 kg of erucic acid, and 2 kg of isooleic acid were mixed, stirred, heated to 120°C, and maintained at this temperature for 2 hours.

[0049] s2: After uniformly mixing 0.01 kg N, N-dimethylethanolamine and 1.5 kg propylene glycol methyl ether, add dropwise to the solution obtained in step 1. The addition is completed within 30 min. The reaction is continued until the acid value is <3 mg KOH / g to obtain a prefabricated epoxy resin.

[0050] The preparation method of the pigment slurry includes: taking 7 kg of modified epoxy resin emulsion, 2.5 kg of pigment, 1.5 kg of ethyl acetate, 1.5 kg of butyl acetate and 0.2 kg of wetting dispersant, then mixing them evenly at 1500 rpm, and then grinding them to a fineness of less than 15 μm to obtain the pigment slurry.

[0051] Example 3 A modified epoxy resin spray paint, which is different from Example 1 in that it includes: 2.2 kg of modified epoxy resin emulsion, 1.5 kg of caprolactone acrylate, 2 kg of pigment slurry, 3.5 kg of solvent, 3.2 kg of dimethyl ether, 0.02 kg of nano-hydroxyapatite, 0.04 kg of water-based bentonite, and 0.08 kg of dimethyl silicone oil.

[0052] The solvent is a mixture of 1.5 kg ethyl acetate, 1.5 kg n-butanol, and 0.5 kg acetone.

[0053] Wherein, the preparation of modified epoxy resin emulsion comprises the following steps: Step 1: Under a nitrogen atmosphere, take 10 kg of epoxy resin, add 11.5 kg of propylene glycol methyl ether, and heat to 60°C while stirring until the epoxy resin is completely dissolved. Then add 1.5 kg of acetone and 0.025 kg of initiator, and keep the reaction warm for 30 minutes.

[0054] Step 2: Heat the solution obtained in step 1 to 80°C, and then dropwise add a mixed solution consisting of 0.035 kg initiator, 2.5 kg acrylic acid, 1.5 kg methacrylic acid, 0.8 kg hydroxypropyl acrylate, and 7 kg butyl acrylate. The addition should be completed within 1.5 hours, and the mixture should be kept warm for 2.5 hours.

[0055] Step 3: Triethylamine was added dropwise to the solution obtained in step 2 until the pH value reached 8.5.

[0056] Step 4: Slowly add deionized water to the solution obtained in step 3 to make the solid content reach 55%, and then centrifuge until it is evenly dispersed to obtain a modified epoxy resin emulsion.

[0057] Wherein, the initiator is benzoyl peroxide.

[0058] The epoxy resin is a mixture of epoxy resin E-51 and prefabricated epoxy resin at a mass ratio of 1:1.5.

[0059] Wherein, the preparation method of prefabricated epoxy resin comprises: s1: Under a nitrogen atmosphere, 10 kg of epoxy resin E-51, 4 kg of styrene sulfonic acid, 5 kg of erucic acid, and 2.5 kg of isooleic acid were mixed, stirred, heated to 110°C, and maintained at this temperature for 2 hours.

[0060] s2: After uniformly mixing 0.015 kg N, N-dimethylethanolamine and 1.8 kg propylene glycol methyl ether, add dropwise to the solution obtained in step 1. The addition is completed within 30 min. The reaction is continued until the acid value is <3 mg KOH / g to obtain a prefabricated epoxy resin.

[0061] The preparation method of the pigment slurry includes: taking 6.5 kg of modified epoxy resin emulsion, 2 kg of pigment, 1.2 kg of ethyl acetate, 1.8 kg of butyl acetate and 0.15 kg of wetting dispersant, then mixing them evenly at 1200 rpm, and then grinding them to a fineness of less than 15 μm to obtain the pigment slurry.

[0062] Example 4 A modified epoxy resin spray paint, which is different from Example 1 in that the epoxy resin added in step 1 of preparing the modified epoxy resin emulsion is epoxy resin E-51.

[0063] Comparative Example 1 A modified epoxy resin spray paint, which is different from Example 4 in that caprolactone acrylate is replaced by modified epoxy resin emulsion in equal amounts.

[0064] Comparative Example 2 A modified epoxy resin spray paint, which is different from Example 4 in that in step 2 of preparing the modified epoxy resin emulsion, an equal amount of hydroxypropyl acrylate is replaced by ethyl acrylate.

[0065] Comparative Example 3 A modified epoxy resin spray paint, which is different from Example 4 in that an equal amount of nano-hydroxyapatite is replaced by nano-silicon dioxide.

[0066] Comparative Example 4 A modified epoxy resin spray paint, which is different from Example 4 in that an equal amount of water-based bentonite is replaced by attapulgite clay.

[0067] Comparative Example 5 A modified epoxy resin spray paint, which is different from Example 4 in that dimethyl silicone oil is replaced by acrylated polysiloxane in equal amounts.

[0068] Performance testing: Add a certain amount of water-based curing agent to the modified epoxy resin spray paint, stir evenly, and measure the adhesion according to GB / T9286-2021, the impact resistance according to GB / T1732-2020, the water resistance according to GB / T1733-1993, the salt spray resistance according to GB / T1771-2007, the hardness according to GB / T6739-2022, and the glossiness according to GB / T8941-2013.

[0069] The above test results are shown in Table 2.

[0070] Table 2: Specifically combined with the analysis of Examples 1-4 and Comparative Examples 1-5, it can be seen that the modified epoxy resin spray paint of the examples of the present application has good adhesion, impact resistance, wear resistance and corrosion resistance, and the paint film of Examples 1-4 of the present application has good gloss. It can be seen that the modified epoxy resin spray paint of Examples 1-4 of the present application has good comprehensive performance.

[0071] Specifically analyzing Example 1 and Example 4, Example 4 does not add prefabricated epoxy resin, and Example 1 has good comprehensive performance. It can be seen that the present application can further improve the comprehensive performance of the paint layer by modifying the prefabricated epoxy resin and introducing styrene sulfonic acid, erucic acid and isooleic acid.

[0072] Specifically combined with the analysis of Example 4 and Comparative Examples 1-5, Comparative Example 1 did not add caprolactone acrylate, Comparative Example 2 replaced the hydroxypropyl acrylate in step 2 of preparing the modified epoxy resin emulsion with ethyl acrylate in an equal amount, and Comparative Examples 3-5 replaced the three additives of nano hydroxyapatite, water-based bentonite and dimethyl silicone oil respectively. Further analysis showed that caprolactone acrylate played a key role in improving the flexibility and corrosion resistance of the paint film of the present application, and hydroxypropyl acrylate was more effective in improving the adhesion performance and water penetration resistance of the paint film. The selection of the three additives of nano hydroxyapatite, water-based bentonite and dimethyl silicone oil can further optimize the physical and chemical properties of the paint film and improve the comprehensive performance of the paint film.

[0073] This specific embodiment is merely an explanation of the present application and is not a limitation of the present application. After reading this specification, those skilled in the art may make modifications to the present embodiment without any creative contribution as needed, but such modifications are protected by the patent law as long as they are within the scope of the claims of the present application.

Claims

1. A modified epoxy resin spray paint, characterized in that: The invention comprises the following components in parts by weight: 20-25 parts of modified epoxy resin emulsion, 10-20 parts of caprolactone acrylate, 15-25 parts of pigment slurry, 30-40 parts of solvent, 30-35 parts of dimethyl ether, 0.1-0.5 parts of nano-hydroxyapatite, 0.1-0.5 parts of water-based bentonite, and 0.5-1 parts of dimethyl silicone oil; The preparation of the modified epoxy resin emulsion comprises the following steps: Step 1: Under a nitrogen atmosphere, take 10 parts of epoxy resin, add 11-12 parts of propylene glycol methyl ether, raise the temperature to 60°C while stirring until the epoxy resin is completely dissolved, then add 1-2 parts of acetone and 0.02-0.03 parts of initiator, and keep the temperature for reaction for 30 minutes; Step 2: Heat the solution obtained in step 1 to 80°C, and then dropwise add a mixed solution consisting of 0.03-0.04 parts of initiator, 2-3 parts of acrylic acid, 1-2 parts of methacrylic acid, 0.5-1 parts of hydroxypropyl acrylate, and 5-8 parts of butyl acrylate. The dropwise addition is completed within 1.5 hours, and the reaction is kept warm for 2-3 hours; Step 3: Triethylamine is added dropwise to the solution obtained in step 2 until the pH value is 8-9; Step 4: Slowly add deionized water to the solution obtained in step 3 to make the solid content reach 50%-60%, and then centrifuge until it is evenly dispersed to obtain a modified epoxy resin emulsion.

2. The method for preparing a modified epoxy resin emulsion according to claim 1, characterized in that: The epoxy resin includes at least epoxy resin E-51.

3. The method for preparing a modified epoxy resin emulsion according to claim 1, characterized in that: The epoxy resin is a mixture of epoxy resin E-51 and prefabricated epoxy resin, the mass ratio of the epoxy resin E-51 to the prefabricated epoxy resin is 1:(1-2), and the preparation method of the prefabricated epoxy resin comprises: Step 1: Under a nitrogen atmosphere, mix 10 parts of epoxy resin E-51, 3-5 parts of styrene sulfonic acid, 4-6 parts of erucic acid, and 2-3 parts of isooleic acid, stir and heat to 100-120°C, and maintain the temperature for 2 hours; Step 2: After uniformly mixing 0.01-0.02 parts of N, N-dimethylethanolamine and 1.5-2 parts of propylene glycol methyl ether, add dropwise to the solution obtained in step 1, and complete the addition within 30 minutes. Continue to react until the acid value is less than 3 mgKOH / g to obtain a prefabricated epoxy resin.

4. The modified epoxy resin spray paint according to claim 1, characterized in that: Calculated by weight of the pigment slurry, the pigment slurry includes the following components: 60-70 parts of modified epoxy resin emulsion, 15-25 parts of pigment, 25-35 parts of solvent, and 1-2 parts of wetting and dispersing agent.

5. The modified epoxy resin spray paint according to claim 4, characterized in that: The preparation method of the pigment slurry comprises: taking modified epoxy resin emulsion, pigment, solvent and wetting dispersant according to the formula, then mixing them evenly at 1000-1500 rpm, and then grinding them to a fineness of less than 15 μm to obtain the pigment slurry.

6. The modified epoxy resin spray paint according to claim 1, characterized in that: The solvent is a combination of ethyl acetate, n-butanol and acetone, and based on the mass fraction of the modified epoxy resin spray paint, comprises 10-15 parts of ethyl acetate, 15-20 parts of n-butanol and 0-5 parts of acetone.

7. The modified epoxy resin spray paint according to claim 1, characterized in that: The initiator is benzoyl peroxide.

8. A method for preparing the modified epoxy resin spray paint according to any one of claims 1 to 7, characterized in that: include: Firstly, the modified epoxy resin emulsion and caprolactone acrylate are uniformly mixed, and then the pigment slurry, solvent, dimethyl ether, nano-hydroxyapatite, water-based bentonite and dimethyl silicone oil are added in sequence, and after uniform mixing, the modified epoxy resin spray paint is obtained.

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