Environmentally friendly antibacterial coating and its preparation method and application

Abstract

The present invention relates to the field of coating technology, and in particular to an environmentally friendly antibacterial coating, a preparation method thereof, and an application thereof. The coating is composed of an antibacterial soybean oil acrylic emulsion, a water-based curing agent, titanium dioxide, nano-copper powder, a leveling agent, and a defoaming agent. The antibacterial emulsion adopts olefinic epoxy soybean oil quaternary ammonium salt as a functional monomer and is prepared by semi-continuous emulsion polymerization. The quaternary ammonium salt active groups of the olefinic epoxy soybean oil quaternary ammonium salt give the coating strong antibacterial properties, and are firmly anchored to the surface through chemical cross-linking, thereby avoiding the problem of migration or loss of antibacterial components in traditional antibacterial coatings, and exhibiting excellent adhesion, hardness, and impact resistance. At the same time, the design based on epoxy soybean oil gives the coating green and environmentally friendly characteristics, meets the requirements of sustainable development, and can be widely used in high antibacterial and durability scenarios such as medical treatment and food processing.

Description

Technical Field

[0001] The present invention relates to the technical field of coatings, and in particular to an environmentally friendly antibacterial coating and a preparation method and application thereof. Background Art

[0002] With the increasing requirements for public health and safety and the increasingly serious problem of bacterial resistance, the coatings industry has an increasing demand for functional coatings with high-efficiency antibacterial properties. Traditional antibacterial coatings often rely on the addition of antibacterial agents to achieve antibacterial properties, but antibacterial agents are easily migrated and lost under the continuous action of aging, erosion or complex environments, resulting in a significant decrease in the antibacterial effect. In addition, the mechanical properties of such coatings are often insufficient, such as poor hardness and adhesion, and they are prone to peeling or failure when subjected to external impact, which limits their practical application. At the same time, different scenarios have high requirements for long-term antibacterial performance. For example, in medical, food processing, public facilities and other application fields, it is hoped that the coatings can have a long-term inhibitory effect on bacteria while maintaining the appearance and performance of the coating.

[0003] Some functionalized antimicrobial coatings currently on the market attempt to enhance their antimicrobial properties by adding nano-antimicrobial agents, metal ions, or organic antimicrobial agents. However, these materials often suffer from weak adhesion, brittle coatings, and unstable antimicrobial properties. Furthermore, many metal ions are susceptible to leaching into the environment, potentially posing a threat to ecosystems. Against this backdrop, effectively improving the performance of antimicrobial coatings and developing materials with enhanced mechanical stability, long-lasting antimicrobial efficacy, and environmental friendliness are pressing challenges in the technology. Summary of the Invention

[0004] In view of this, the purpose of the present invention is to provide an environmentally friendly antibacterial coating and its preparation method and application, so as to solve the problem that the antibacterial components of the existing antibacterial coating are easily migrated and shed.

[0005] Based on the above objectives, the present invention provides an environmentally friendly antibacterial coating, which is prepared from the following raw materials, by weight: 400-600 parts of antibacterial soybean oil acrylic emulsion, 60-90 parts of water-based curing agent, 25-35 parts of titanium dioxide, 3-5 parts of nano copper powder, 5-15 parts of leveling agent and 3-10 parts of defoaming agent.

[0006] Preferably, the water-based curing agent is Covestro XP2655.

[0007] Preferably, the titanium dioxide is rutile titanium dioxide with an average particle size of 150-250 nm.

[0008] Preferably, the average particle size of the nano copper powder is 10-30 nm.

[0009] Preferably, the leveling agent is BYK-346.

[0010] Preferably, the defoaming agent is BYK-024.

[0011] The preparation steps of the antibacterial soybean oil acrylic emulsion are as follows:

[0012] (1) Treating epoxidized soybean oil with hydrochloric acid to obtain chloroepoxidized soybean oil;

[0013] (2) Add chloroepoxidized soybean oil, dimethylaminoethyl methacrylate and 3-dimethylamino-1-propanol to tetrahydrofuran, raise the temperature to 48-52°C under nitrogen atmosphere, stir and react for 70-75 hours, and rotary evaporate to obtain olefinated epoxidized soybean oil quaternary ammonium salt;

[0014] (3) Antibacterial soybean oil acrylic emulsion was prepared by semi-continuous emulsion polymerization using lauryl methacrylate, butyl acrylate, hydroxyethyl methacrylate and alkylene epoxidized soybean oil quaternary ammonium salt as polymerization monomers.

[0015] Preferably, the epoxidation value of the epoxidized soybean oil in step (1) is 6.6%.

[0016] Preferably, the specific preparation steps of the chloro-epoxidized soybean oil are as follows: adding the epoxidized soybean oil to acetone, heating to 38-42° C., adding a hydrochloric acid aqueous solution dropwise, stirring for 100-150 minutes, and purifying to obtain the chloro-epoxidized soybean oil;

[0017] Preferably, the weight ratio of the epoxidized soybean oil, acetone and hydrochloric acid aqueous solution is 12-18:40-60:7-10;

[0018] Preferably, the concentration of the hydrochloric acid aqueous solution is 32wt%-40wt%.

[0019] Preferably, in step (2), the weight ratio of chloroepoxidized soybean oil, dimethylaminoethyl methacrylate, 3-dimethylamino-1-propanol and tetrahydrofuran is 12-18:5-7.5:4.2-6.2:80-120.

[0020] Preferably, in step (3), the weight ratio of lauryl methacrylate, butyl acrylate, hydroxyethyl methacrylate and olefinated epoxy soybean oil quaternary ammonium salt is 35-50:25-35:22-28:12-18.

[0021] Preferably, the specific steps of the semi-continuous emulsion polymerization method in step (3) are:

[0022] S1: Add the emulsifier to deionized water, heat it to 38-42°C, add the polymerization monomer, and stir at 1100-1300 rpm for 20-30 minutes to obtain a pre-emulsion;

[0023] S2: Add 3.5-4.8 g of ammonium persulfate to 43-57 g of deionized water and stir for 10-20 minutes to obtain an initiator solution;

[0024] S3: Mix 1 / 3 weight of the pre-emulsion prepared in step S1 and 1 / 3 weight of the initiator solution prepared in step S2, raise the temperature to 76-80°C at 2°C / min under nitrogen protection, stir for 20-40 minutes, and then simultaneously add 2 / 3 weight of the pre-emulsion prepared in step S1 and 2 / 3 weight of the initiator solution prepared in step S2 dropwise. After the addition is complete, continue stirring for 2.5-3.5 hours, and cool to room temperature to obtain an antibacterial soybean oil acrylic emulsion.

[0025] Preferably, the emulsifier in step S1 is a mixture of sodium lauryl sulfate and alkylphenol polyoxyethylene ether in a weight ratio of 3-4:1.8-2.4.

[0026] Preferably, in step S1, the weight ratio of the emulsifier, deionized water, and polymerization monomer is 4.8-6.4:300-400:94-131.

[0027] Preferably, the weight ratio of ammonium persulfate to deionized water in step S2 is 3.5-4.8:43-57.

[0028] Preferably, the weight ratio of the pre-emulsion to the initiator solution in step S3 is 398.8-537.4:46.5-61.8.

[0029] Furthermore, the present invention also provides a method for preparing an environmentally friendly antibacterial coating, comprising the following steps: mixing an antibacterial soybean oil acrylic emulsion and a water-based curing agent, stirring at a speed of 200-400 rpm for 10-20 minutes, then adding titanium dioxide, nano-copper powder, a leveling agent, and a defoaming agent, and continuing to stir for 20-40 minutes to obtain an environmentally friendly antibacterial coating.

[0030] Beneficial effects of the present invention:

[0031] The coating provided by the present invention has significantly improved antimicrobial properties. The quaternary ammonium salt of olefinated epoxidized soybean oil, when used as a functional monomer, forms a high density of quaternary ammonium salt active groups on the coating surface after being combined with the coating matrix. This polymer structure design imparts strong antimicrobial properties to the surface coating. Furthermore, the specially modified quaternary ammonium salt molecules can form chemical crosslinks through copolymerization, firmly anchoring to the coating surface. This molecular design effectively avoids the problem of antimicrobial components in traditional antimicrobial coatings migrating or losing due to aging, cleaning, or external environmental influences.

[0032] The coating provided by the present invention has excellent mechanical properties, exhibiting outstanding adhesion and hardness, and possesses outstanding impact resistance. This is due to the fact that the functional groups in the alkylene-epoxidized soybean oil quaternary ammonium salt can participate in grafting and crosslinking reactions, forming a dense coating network structure together with other monomers, thereby enhancing the overall mechanical strength of the coating film. The coating also significantly improves its stability under environmental and mechanical stresses, meeting the requirements of long-term use under harsh conditions.

[0033] The coating provided by this invention boasts environmentally friendly properties and broad applicability. Its epoxy soybean oil-based design makes it environmentally friendly and compliant with current environmental protection and sustainable development requirements. Its antimicrobial properties, aging resistance, and excellent mechanical properties make it suitable for a wide range of applications requiring high levels of antimicrobial resistance and durability, such as healthcare, food processing, and consumer goods. DETAILED DESCRIPTION

[0034] In order to make the objectives, technical solutions and advantages of the present invention more clearly understood, the present invention is further described in detail below with reference to specific embodiments.

[0035] The epoxidized soybean oil in the specific embodiment of the present invention was purchased from Shanghai Aladdin Biochemical Technology Co., Ltd. with the product number E107074 and an epoxy value of 6.6%. Example

[0036] (1) Add 12 g of epoxidized soybean oil to 40 g of acetone, heat to 38 °C, add 7 g of 36 wt% hydrochloric acid solution dropwise, stir for 100 min, evaporate, dissolve the product with ethyl acetate, and then wash repeatedly with deionized water for 3 times. Take the organic layer and dry it in vacuum to obtain chloroepoxidized soybean oil;

[0037] (2) 12 g of chloroepoxidized soybean oil, 5 g of dimethylaminoethyl methacrylate, and 4.2 g of 3-dimethylamino-1-propanol were added to 80 g of tetrahydrofuran, heated to 48 ° C under a nitrogen atmosphere, stirred for 70 h, and rotary evaporated to obtain olefinated epoxidized soybean oil quaternary ammonium salt;

[0038] (3) Add 3 g of sodium lauryl sulfate and 1.8 g of alkylphenol polyoxyethylene ether OP-10 to 300 g of deionized water, heat to 38 °C, add 35 g of lauryl methacrylate, 25 g of butyl acrylate, 22 g of hydroxyethyl methacrylate and 12 g of alkylated epoxidized soybean oil quaternary ammonium salt in sequence, and stir at 1100 rpm for 20 min to obtain a pre-emulsion;

[0039] (4) Add 3.5 g of ammonium persulfate to 43 g of deionized water and stir for 10 min to obtain an initiator solution;

[0040] (5) 1 / 3 weight of the pre-emulsion prepared in step (3) and 1 / 3 weight of the initiator solution prepared in step (4) were mixed, and under nitrogen protection, the temperature was raised to 76°C at 1°C / min, and stirred for 20 minutes. Then, 2 / 3 weight of the pre-emulsion prepared in step (3) and 2 / 3 weight of the initiator solution prepared in step (4) were simultaneously added dropwise. After the addition was completed, the mixture was stirred for 2.5 hours and cooled to room temperature to obtain an antibacterial soybean oil acrylic emulsion;

[0041] (6) 400 g of antibacterial soybean oil acrylic emulsion and 60 g of water-based curing agent (Covestro XP2655) were mixed and stirred at 200 rpm for 10 min. Then, 25 g of rutile titanium dioxide (average particle size 200 nm), 3 g of nano copper powder (average particle size 20 nm), 5 g of leveling agent BYK-346, and 3 g of defoaming agent BYK-024 were added and stirred for 20 min to obtain an environmentally friendly antibacterial coating. Example

[0042] (1) Add 15 g of epoxidized soybean oil to 50 g of acetone, heat to 40 °C, add 8 g of 36 wt% hydrochloric acid solution dropwise, stir for 120 min, evaporate, dissolve the product with ethyl acetate, and then wash repeatedly with deionized water for 3 times. Take the organic layer and dry it in vacuum to obtain chloroepoxidized soybean oil;

[0043] (2) 15 g of chloroepoxidized soybean oil, 6.2 g of dimethylaminoethyl methacrylate, and 5.2 g of 3-dimethylamino-1-propanol were added to 100 g of tetrahydrofuran, heated to 50°C under a nitrogen atmosphere, stirred and reacted for 72 h, and rotary evaporated to obtain olefinated epoxidized soybean oil quaternary ammonium salt;

[0044] (3) Add 3.5 g of sodium lauryl sulfate and 2.1 g of alkylphenol polyoxyethylene ether OP-10 to 350 g of deionized water, heat to 40 °C, add 40 g of lauryl methacrylate, 30 g of butyl acrylate, 25 g of hydroxyethyl methacrylate and 15 g of alkylated epoxidized soybean oil quaternary ammonium salt in sequence, and stir at 1200 rpm for 25 min to obtain a pre-emulsion;

[0045] (4) Add 4.2 g of ammonium persulfate to 50 g of deionized water and stir for 15 min to obtain an initiator solution;

[0046] (5) 1 / 3 weight of the pre-emulsion prepared in step (3) and 1 / 3 weight of the initiator solution prepared in step (4) were mixed, and under nitrogen protection, the temperature was raised to 78°C at 2°C / min, and stirred for 30 minutes. Then, 2 / 3 weight of the pre-emulsion prepared in step (3) and 2 / 3 weight of the initiator solution prepared in step (4) were simultaneously added dropwise. After the addition was completed, the mixture was stirred for 3 hours and cooled to room temperature to obtain an antibacterial soybean oil acrylic emulsion;

[0047] (6) 500 g of antibacterial soybean oil acrylic emulsion and 75 g of water-based curing agent (Covestro XP2655) were mixed and stirred at 300 rpm for 15 min. Then, 30 g of rutile titanium dioxide (average particle size 200 nm), 4 g of nano copper powder (average particle size 20 nm), 10 g of leveling agent BYK-346, and 5 g of defoaming agent BYK-024 were added and stirred for 30 min to obtain an environmentally friendly antibacterial coating. Example

[0048] (1) Add 18 g of epoxidized soybean oil to 60 g of acetone, heat to 42 °C, add 10 g of 36 wt% hydrochloric acid solution dropwise, stir for 150 min, evaporate, dissolve the product with ethyl acetate, and then wash repeatedly with deionized water for 3 times. Take the organic layer and dry it in vacuum to obtain chloroepoxidized soybean oil;

[0049] (2) 18 g of chloroepoxidized soybean oil, 7.5 g of dimethylaminoethyl methacrylate and 6.2 g of 3-dimethylamino-1-propanol were added to 120 g of tetrahydrofuran, heated to 52 °C under a nitrogen atmosphere, stirred and reacted for 75 h, and then rotary evaporated to obtain olefinated epoxidized soybean oil quaternary ammonium salt;

[0050] (3) 4 g of sodium lauryl sulfate and 2.4 g of alkylphenol polyoxyethylene ether OP-10 were added to 400 g of deionized water, and the temperature was raised to 42 °C. 50 g of lauryl methacrylate, 35 g of butyl acrylate, 28 g of hydroxyethyl methacrylate, and 18 g of alkylated epoxidized soybean oil quaternary ammonium salt were added in sequence, and the mixture was stirred at 1300 rpm for 30 min to obtain a pre-emulsion.

[0051] (4) Add 4.8 g of ammonium persulfate to 57 g of deionized water and stir for 20 min to obtain an initiator solution;

[0052] (5) 1 / 3 weight of the pre-emulsion prepared in step (3) and 1 / 3 weight of the initiator solution prepared in step (4) were mixed, and under nitrogen protection, the temperature was raised to 80°C at 3°C / min, and stirred for 40 minutes. Then, 2 / 3 weight of the pre-emulsion prepared in step (3) and 2 / 3 weight of the initiator solution prepared in step (4) were simultaneously added dropwise. After the addition was completed, the mixture was stirred for 3.5 hours and cooled to room temperature to obtain an antibacterial soybean oil acrylic emulsion;

[0053] (6) 600 g of antibacterial soybean oil acrylic emulsion and 90 g of water-based curing agent (Covestro XP2655) were mixed and stirred at 400 rpm for 20 min. Then, 35 g of rutile titanium dioxide (average particle size 200 nm), 5 g of nano copper powder (average particle size 20 nm), 15 g of leveling agent BYK-346, and 10 g of defoaming agent BYK-024 were added. The mixture was stirred for 40 min to obtain an environmentally friendly antibacterial coating.

[0054] Comparative Example 1:

[0055] The difference between Comparative Example 1 and Example 2 is that the alkylene-epoxidized soybean oil quaternary ammonium salt in step (3) is replaced by epoxy soybean oil;

[0056] Comparative Example 2:

[0057] The difference between Comparative Example 2 and Example 2 is that the dimethylaminoethyl methacrylate in step (2) is replaced by an equal molar amount of 3-dimethylamino-1-propanol;

[0058] Comparative Example 3:

[0059] Comparative Example 3 differs from Example 2 in that: 3-dimethylamino-1-propanol in step (2) is replaced by an equal molar amount of dimethylaminoethyl methacrylate;

[0060] Comparative Example 4:

[0061] Comparative Example 4 differs from Example 2 in that: dimethylaminoethyl methacrylate and 3-dimethylamino-1-propanol in step (2) are replaced by an equimolar amount of dodecyltrimethylammonium chloride;

[0062] Performance testing:

[0063] Antibacterial performance test: According to GB / T 21866-2008, Escherichia coli (ATCC 25922) was selected as the test bacteria. The coating sample was evenly coated on a sterile glass substrate with a coating thickness of (50±5) μm. After curing at room temperature for 7 days, a test piece was prepared. Using a sterile pipette, 0.2 mL of bacterial suspension (concentration 1×10 5 CFU / mL), covered with sterile polyethylene film, and incubated in a constant temperature and humidity chamber (temperature 37°C ± 1°C, relative humidity ≥ 90%) for 24 hours. The specimen surface was rinsed with physiological saline containing a neutralizer, and the sample was inoculated onto nutrient agar plates after gradient dilution. After incubation at 37°C for 48 hours, the colonies were counted and the inhibition rate was calculated according to the formula: Inhibition rate (%) = (number of colonies in the blank control group - number of colonies in the test group) / number of colonies in the blank control group × 100%. The results are shown in Table 1.

[0064] Antimicrobial durability test: The coating sample was evenly coated on a sterile glass substrate with a coating thickness of (50±5) μm. After curing at room temperature for 7 days, a test piece was prepared. The sample was placed in a xenon lamp aging chamber (irradiation intensity 0.55 W / m², circulating deionized water spray) for 200 hours of accelerated aging. The antimicrobial performance test process was then repeated to test the inhibition rate. The results are shown in Table 1.

[0065] Mechanical Properties: According to GB / T 1720-2020, a coating with a dry film thickness of (25±2) μm was applied to standard tinplate using a film applicator. After curing at room temperature for 7 days, a 1 mm × 1 mm grid pattern was scratched using a crosshatch cutter. Adhesion was tested by peeling with 3M tape. The results are shown in Table 1. Hardness was tested by scratching with 13 grades of Zhonghua brand high-grade drawing pencils, ranging from 6B to 6H, according to GB / T 6739-2006. The results are shown in Table 1. According to GB / T 1732-2020, a QCJ impact tester was used. After a 1 kg weight was dropped from a height of 50 cm, the coating was observed for cracks, wrinkles, and flaking. If no cracks, wrinkles, or flaking were observed, the test was repeated at successively higher heights, increasing the height by 5 cm or multiples of 5 cm, until cracks, wrinkles, or flaking were observed. If cracks, wrinkles, or peeling are observed, the test is repeated at successively lower positions until no cracks, wrinkles, or peeling are observed. Each lowering is 5 cm or multiples of 5 cm. The results are shown in Table 1.

[0066] Table 1 Performance test results

[0067] Antibacterial rate / % Antibacterial rate after aging / % Adhesion / Grade Hardness / Grade Impact resistance / cm Example 1 98.9 96.3 1 3H 50 Example 2 99.3 97.4 1 3H 50 Example 3 99.6 97.8 1 3H 50 Comparative Example 1 75.4 54.3 2 H 40 Comparative Example 2 95.8 90.3 1 2H 45 Comparative Example 3 84.5 78.3 2 2H 45 Comparative Example 4 97.1 75.2 2 H 35

[0068] Data Analysis:

[0069] As can be seen from the data of Examples 1-3 in Table 1, the coatings prepared by the present invention exhibit good adhesion, hardness, and high antibacterial effect, and can maintain excellent antibacterial and mechanical properties under aging conditions. This shows that the combination of material formulation and preparation process effectively modifies the structure of the coating, so that it not only has initial antibacterial activity, but also can maintain stable functions under aging conditions. This may be due to the introduction of alkylated epoxidized soybean oil quaternary ammonium salt in the formula, which can form a strong bond with the coating substrate and impart durable antibacterial properties to the surface without significantly affecting the mechanical strength of the coating. This optimized combination design makes the coating suitable for long-term application and maintains good performance in harsh environments, which has significant advantages from the perspective of practical application.

[0070] As can be seen from the data of Example 2 and Comparative Example 1 in Table 1, Example 2 exhibits significant advantages over Comparative Example 1 in terms of antibacterial performance, antibacterial performance after aging, adhesion, and hardness. This modification effect may be attributed to the use of an olefin-epoxidized soybean oil quaternary ammonium salt, which not only provides higher molecular activity but also significantly enhances the antibacterial effect of the coating at the molecular level through the unique quaternary ammonium salt functional groups.

[0071] The data from Example 2 and Comparative Example 2 in Table 1 show that the coating of Example 2 exhibits superior antimicrobial stability after aging, as well as mechanical properties such as hardness and adhesion. This is likely due to the inclusion of dimethylaminoethyl methacrylate, whose double bonds can participate in copolymerization reactions, forming a grafted cross-linked network. This not only improves the mechanical stability of the coating but also reduces environmental erosion through a more compact structure, thereby imparting superior anti-aging properties to the material.

[0072] As can be seen from the data of embodiment 2 and comparative example 3 in table 1, embodiment 2 is all better than comparative example 3 in terms of antimicrobial property, hardness, etc., this may be due to the hydroxyl group of 3-dimethylamino-1-propanol may give alkenylation epoxy soybean oil quaternary ammonium salt stronger hydrophilicity, impel this component to be preferentially distributed on latex particle surface during copolymerization, and will not be embedded in latex particle inside, further make coating surface quaternary ammonium salt distribution density higher, not only directly enhance the contact efficiency of antimicrobial group and bacteria, simultaneously by solidification crosslinking, quaternary ammonium salt is stably anchored on coating surface, avoid the migration loss of antimicrobial component in aging process.In addition, hydroxyl group may react with aqueous curing agent as crosslinking site, further enhances interfacial bonding force and coating hardness, thus shows synergistic optimization effect on the mechanical properties such as adhesion, impact resistance.

[0073] It can be seen from the data of Example 2 and Comparative Example 4 in Table 1 that, compared with the direct addition of quaternary ammonium salt, the olefinated epoxidized soybean oil quaternary ammonium salt provided by the present invention further improves the antibacterial performance, adhesion and impact resistance of the coating after aging. This is mainly because dodecyltrimethylammonium chloride easily migrates in the coating and easily falls off from the coating surface during the aging and scouring process.

[0074] Those skilled in the art should understand that the discussion of any of the above embodiments is merely illustrative and is not intended to imply that the scope of the present invention is limited to these examples. Within the scope of the present invention, the technical features in the above embodiments or different embodiments may be combined, the steps may be implemented in any order, and there are many other variations of the different aspects of the present invention as described above, which are not provided in detail for the sake of simplicity.

Claims

1. An environmentally friendly antibacterial coating, characterized in that: The invention is prepared from the following raw materials in parts by weight: 400-600 parts of antibacterial soybean oil acrylic emulsion, 60-90 parts of water-based curing agent, 25-35 parts of titanium dioxide, 3-5 parts of nano copper powder, 5-15 parts of leveling agent and 3-10 parts of defoaming agent; The preparation steps of the antibacterial soybean oil acrylic emulsion are as follows: (1) Treating epoxidized soybean oil with hydrochloric acid to obtain chloroepoxidized soybean oil; (2) Add chloroepoxidized soybean oil, dimethylaminoethyl methacrylate and 3-dimethylamino-1-propanol to tetrahydrofuran, raise the temperature to 48-52°C under nitrogen atmosphere, stir and react for 70-75 hours, and rotary evaporate to obtain olefinated epoxidized soybean oil quaternary ammonium salt; (3) Using lauryl methacrylate, butyl acrylate, hydroxyethyl methacrylate and alkylene-epoxidized soybean oil quaternary ammonium salt as polymerization monomers, an antibacterial soybean oil acrylic emulsion was prepared by semi-continuous emulsion polymerization. In the step (2), the weight ratio of chloroepoxidized soybean oil, dimethylaminoethyl methacrylate, 3-dimethylamino-1-propanol and tetrahydrofuran is 12-18:5-7.5:4.2-6.2:80-120; In the step (3), the weight ratio of lauryl methacrylate, butyl acrylate, hydroxyethyl methacrylate and olefinated epoxy soybean oil quaternary ammonium salt is 35-50:25-35:22-28:12-18.

2. The environmentally friendly antibacterial coating according to claim 1, characterized in that: The water-based curing agent is Covestro XP2655; the titanium dioxide is rutile titanium dioxide with an average particle size of 150-250 nm; the average particle size of the nano copper powder is 10-30 nm; the leveling agent is BYK-346; and the defoaming agent is BYK-024.

3. The environmentally friendly antibacterial coating according to claim 1, characterized in that: The specific preparation steps of the chloroepoxidized soybean oil in step (1) are as follows: adding the epoxidized soybean oil to acetone, heating to 38-42° C., adding a hydrochloric acid aqueous solution dropwise, stirring for 100-150 minutes, and purifying to obtain the chloroepoxidized soybean oil.

4. The environmentally friendly antibacterial coating according to claim 3, characterized in that: The weight ratio of the epoxidized soybean oil, acetone and hydrochloric acid aqueous solution is 12-18:40-60:7-10; and the concentration of the hydrochloric acid aqueous solution is 32wt%-40wt%.

5. The environmentally friendly antibacterial coating according to claim 1, characterized in that: The specific steps of the semi-continuous emulsion polymerization method in step (3) are: S1: Add the emulsifier to deionized water, heat it to 38-42°C, add the polymerization monomer, and stir at 1100-1300 rpm for 20-30 minutes to obtain a pre-emulsion; S2: Add 3.5-4.8 g of ammonium persulfate to 43-57 g of deionized water and stir for 10-20 minutes to obtain an initiator solution; S3: Mix 1 / 3 weight of the pre-emulsion prepared in step S1 and 1 / 3 weight of the initiator solution prepared in step S2, raise the temperature to 76-80°C at 2°C / min under nitrogen protection, stir for 20-40 minutes, and then simultaneously add 2 / 3 weight of the pre-emulsion prepared in step S1 and 2 / 3 weight of the initiator solution prepared in step S2 dropwise. After the addition is complete, continue stirring for 2.5-3.5 hours, and cool to room temperature to obtain an antibacterial soybean oil acrylic emulsion.

6. The environmentally friendly antibacterial coating according to claim 5, characterized in that: In step S1, the emulsifier is a mixture of sodium lauryl sulfate and alkylphenol polyoxyethylene ether in a weight ratio of 3-4:1.8-2.4; in step S1, the weight ratio of the emulsifier, deionized water, and polymerization monomer is 4.8-6.4:300-400:94-131; in step S2, the weight ratio of ammonium persulfate and deionized water is 3.5-4.8:43-57; and in step S3, the weight ratio of the pre-emulsion and the initiator solution is 398.8-537.4:46.5-61.

8.

7. A method for preparing the environmentally friendly antibacterial coating according to any one of claims 1 to 6, characterized in that: The following steps are involved: The antibacterial soybean oil acrylic emulsion and the water-based curing agent are mixed, stirred at a speed of 200-400 rpm for 10-20 minutes, titanium dioxide, nano copper powder, leveling agent, and defoaming agent are added, and stirring is continued for 20-40 minutes to obtain an environmentally friendly antibacterial coating.