Environment-friendly antibacterial coating as well as preparation method and application thereof

Abstract

The invention relates to the technical field of coatings, in particular to an environment-friendly antibacterial coating as well as a preparation method and application thereof. The coating is prepared from antibacterial soybean oil acrylic emulsion, a water-based curing agent, titanium dioxide, nano copper powder, a flatting agent and a defoaming agent. Wherein the antibacterial emulsion is prepared by adopting alkenylated epoxidized soybean oil quaternary ammonium salt as a functional monomer through a semi-continuous emulsion polymerization method, quaternary ammonium salt active groups of the alkenylated epoxidized soybean oil quaternary ammonium salt endow the coating with strong antibacterial performance, and the surface is firmly anchored through chemical crosslinking; the problem of migration or loss of antibacterial components in a traditional antibacterial coating is avoided, and excellent adhesive force, hardness and impact resistance are shown. Meanwhile, the coating is designed on the basis of the epoxidized soybean oil, so that the coating has the characteristics of greenness and environmental protection, meets the requirements of sustainable development, and can be widely applied to high-antibacterial-property and durable scenes such as medical treatment and food processing.

Description

Technical Field

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

[0002] With the improvement of public health safety requirements and the increasingly serious problem of bacterial drug resistance, the coating industry has an increasing demand for functional coatings with high antibacterial performance. Traditional antibacterial coatings often rely on adding antibacterial agents to achieve antibacterial performance. However, antibacterial agents are prone to migrate and lose under the continuous action of aging, scouring, or complex environments, resulting in a significant decline in antibacterial effects. In addition, the mechanical properties of such coatings are often insufficient, such as poor hardness and adhesion, and are prone to peeling or failure when subjected to external force impacts, which limits their practical applications. At the same time, different scenarios have relatively high requirements for the long-term antibacterial performance. For example, in application fields such as medical treatment, food processing, and public facilities, it is desired that the coating can maintain the coating appearance and performance while having a long-term inhibitory effect on bacteria.

[0003] Some functional antibacterial coatings on the market currently attempt to enhance antibacterial performance by adding nano-antibacterial agents, metal ions, or organic antibacterial agents. However, these materials usually have problems such as weak adhesion, strong brittleness of the coating, and unstable antibacterial performance. Moreover, many metal ions may pose a potential threat to the ecosystem due to their easy dissolution into the environment. In this context, how to effectively improve the performance of antibacterial coatings and develop materials with higher mechanical stability, long-lasting antibacterial effects, and environmental friendliness and harmlessness is an urgent problem to be solved in the current technical field. Summary of the Invention

[0004] In view of this, the purpose of the present invention is to provide an environmentally friendly antibacterial coating, a preparation method thereof, and an application thereof to solve the problem that the antibacterial components of existing antibacterial coatings are prone to migrate and fall off.

[0005] Based on the above purpose, 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: (1) Treat epoxy soybean oil with hydrochloric acid to obtain chlorinated epoxy soybean oil; (2) Add chlorinated epoxy soybean oil, dimethylaminoethyl methacrylate and 3-dimethylamino-1-propanol into tetrahydrofuran. Under a nitrogen atmosphere, heat up to 48-52 °C and stir for reaction for 70-75 h. Then perform rotary evaporation to obtain quaternary ammonium salt of alkenylated epoxy soybean oil; (3) Use lauryl methacrylate, butyl acrylate, 2-hydroxyethyl methacrylate and quaternary ammonium salt of alkenylated epoxy soybean oil as polymerization monomers, and prepare the antibacterial soybean oil acrylic emulsion by semi-continuous emulsion polymerization method.

[0012] Preferably, the epoxy value of the epoxy soybean oil in step (1) is 6.6%.

[0013] Preferably, the specific preparation steps of the chlorinated epoxy soybean oil are as follows: Add epoxy soybean oil into acetone, heat up to 38-42 °C, dropwise add hydrochloric acid aqueous solution, stir for 100-150 min, and purify to obtain chlorinated epoxy soybean oil; Preferably, the weight ratio of the epoxy soybean oil, acetone and hydrochloric acid aqueous solution is 12-18:40-60:7-10; Preferably, the concentration of the hydrochloric acid aqueous solution is 32 wt%-40 wt%.

[0014] Preferably, the weight ratio of the chlorinated epoxy soybean oil, dimethylaminoethyl methacrylate, 3-dimethylamino-1-propanol and tetrahydrofuran in step (2) is 12-18:5-7.5:4.2-6.2:80-120.

[0015] Preferably, the weight ratio of lauryl methacrylate, butyl acrylate, 2-hydroxyethyl methacrylate and quaternary ammonium salt of alkenylated epoxy soybean oil in step (3) is 35-50:25-35:22-28:12-18.

[0016] Preferably, the specific steps of the semi-continuous emulsion polymerization method in step (3) are as follows: S1: Add an emulsifier into deionized water, heat up to 38-42 °C, add polymerization monomers, and stir at a speed of 1100-1300 rpm for 20-30 min to obtain a pre-emulsion; S2: Add 3.5-4.8 g of ammonium persulfate into 43-57 g of deionized water, stir for 10-20 min 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. Under nitrogen protection, heat it to 76 - 80 °C at a rate of 2 °C / min, stir for 20 - 40 min, then simultaneously dropwise add 2 / 3 weight of the pre-emulsion prepared in step S1 and 2 / 3 weight of the initiator solution prepared in step S2. After the dropping is completed, continue to stir for 2.5 - 3.5 h, and cool to room temperature to obtain the antibacterial soybean oil acrylic emulsion.

[0017] Preferably, in step S1, the emulsifier is a mixture of sodium dodecyl sulfate and alkylphenol polyoxyethylene ether with a weight ratio of 3 - 4:1.8 - 2.4.

[0018] Preferably, in step S1, the weight ratio of the emulsifier, deionized water, and polymerization monomer is 4.8 - 6.4:300 - 400:94 - 131.

[0019] Preferably, in step S2, the weight ratio of ammonium persulfate and deionized water is 3.5 - 4.8:43 - 57.

[0020] Preferably, in step S3, the weight ratio of the pre-emulsion and the initiator solution is 398.8 - 537.4:46.5 - 61.8.

[0021] Furthermore, the present invention also provides a preparation method of an environmentally friendly antibacterial coating, which includes the following steps: Mix the antibacterial soybean oil acrylic emulsion and a water-based curing agent, stir at a speed of 200 - 400 rpm for 10 - 20 min, then add titanium dioxide, nano copper powder, a leveling agent, and an antifoaming agent, and continue to stir for 20 - 40 min to obtain the environmentally friendly antibacterial coating.

[0022] Advantages of the present invention: The coating provided by the present invention has significantly improved antibacterial performance. After the vinylated epoxy soybean oil quaternary ammonium salt is combined with the coating matrix as a functional monomer, a high-density quaternary ammonium salt active group is formed on the surface of the coating. This polymer structure design endows the surface coating with strong antibacterial performance. Moreover, the quaternary ammonium salt molecules prepared by special modification can form chemical cross-links through copolymerization reactions and are firmly anchored on the surface of the coating. This molecular design effectively avoids the problems of migration or loss of antibacterial components in traditional antibacterial coatings due to aging, cleaning, or external environmental influences.

[0023] The coating provided by the present invention has excellent mechanical properties, showing excellent adhesion and hardness, and has excellent impact resistance. This benefits from the fact that the functional groups in the vinylated epoxy soybean oil quaternary ammonium salt can participate in grafting and cross-linking reactions, jointly forming a dense coating network structure with other monomers, thereby enhancing the overall mechanical strength of the coating film. The stability of the coating under environmental stress and mechanical stress is significantly improved, meeting the use requirements under long-term and harsh conditions.

[0024] The coating provided by the present invention has environmental protection performance and wide applicability. The design based on epoxy soybean oil endows the coating with green environmental protection attributes, meeting the requirements of current environmental protection and sustainable development. Its performance, including antibacterial effect, anti-aging performance and excellent mechanical properties, enables the coating to be widely applied in fields such as medical treatment, food processing, and daily consumer goods that require high levels of antibacterial property and durability. Specific Embodiments

[0025] To make the objectives, technical solutions and advantages of the present invention more clearly understood, the following further details the present invention in conjunction with specific embodiments.

[0026] The epoxy soybean oil in the specific embodiments 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%. Examples

[0027] (1) Add 12 g of epoxy soybean oil to 40 g of acetone, heat up to 38 °C, dropwise add 7 g of hydrochloric acid aqueous solution with a concentration of 36 wt%, stir for 100 min, perform rotary evaporation, dissolve the product with ethyl acetate, and then repeatedly wash with deionized water 3 times. Take the organic layer and dry it under vacuum to obtain chlorinated epoxy soybean oil; (2) Add 12 g of chlorinated epoxy soybean oil, 5 g of dimethylaminoethyl methacrylate, and 4.2 g of 3-dimethylamino-1-propanol to 80 g of tetrahydrofuran. Under a nitrogen atmosphere, heat up to 48 °C and stir for 70 h. Perform rotary evaporation to obtain quaternary ammonium salt of alkenylated epoxy soybean oil; (3) Add 3 g of sodium dodecyl sulfate and 1.8 g of alkylphenol polyoxyethylene ether OP-10 to 300 g of deionized water, heat up to 38 °C, and successively add 35 g of lauryl methacrylate, 25 g of butyl acrylate, 22 g of 2-hydroxyethyl methacrylate, and 12 g of quaternary ammonium salt of alkenylated epoxy soybean oil. Stir at a speed of 1100 rpm for 20 min to obtain a pre-emulsion; (4) Add 3.5 g of ammonium persulfate to 43 g of deionized water and stir for 10 min to obtain an initiator solution; (5) Mix 1 / 3 weight of the pre-emulsion prepared in step (3) and 1 / 3 weight of the initiator solution prepared in step (4). Under nitrogen protection, heat up to 76 °C at a rate of 1 °C / min and stir for 20 min. Then synchronously dropwise add 2 / 3 weight of the pre-emulsion prepared in step (3) and 2 / 3 weight of the initiator solution prepared in step (4). After the dropping is completed, continue to stir for 2.5 h and cool to room temperature to obtain an antibacterial soybean oil acrylate emulsion; (6) Mix 400 g of antibacterial soybean oil acrylic emulsion and 60 g of waterborne curing agent (Covestro XP2655), stir at a speed of 200 rpm for 10 min, then add 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, and continue to stir for 20 min to obtain an environmentally friendly antibacterial coating. Example

[0028] (1) Add 15 g of epoxy soybean oil to 50 g of acetone, heat up to 40 °C, dropwise add 8 g of hydrochloric acid aqueous solution with a concentration of 36 wt%, stir for 120 min, perform rotary evaporation, dissolve the product with ethyl acetate, and then wash it repeatedly with deionized water for 3 times. Take the organic layer and dry it under vacuum to obtain chlorinated epoxy soybean oil. (2) Add 15 g of chlorinated epoxy soybean oil, 6.2 g of dimethylaminoethyl methacrylate, and 5.2 g of 3-dimethylamino-1-propanol to 100 g of tetrahydrofuran. Under a nitrogen atmosphere, heat up to 50 °C and stir and react for 72 h. Perform rotary evaporation to obtain quaternary ammonium salt of alkenylated epoxy soybean oil. (3) Add 3.5 g of sodium dodecyl sulfate and 2.1 g of alkylphenol polyoxyethylene ether OP-10 to 350 g of deionized water, heat up to 40 °C, and sequentially add 40 g of lauryl methacrylate, 30 g of butyl acrylate, 25 g of 2-hydroxyethyl methacrylate, and 15 g of quaternary ammonium salt of alkenylated epoxy soybean oil, and stir at a speed of 1200 rpm for 25 min to obtain a pre-emulsion. (4) Add 4.2 g of ammonium persulfate to 50 g of deionized water and stir for 15 min to obtain an initiator solution. (5) Mix 1 / 3 weight of the pre-emulsion prepared in step (3) and 1 / 3 weight of the initiator solution prepared in step (4). Under nitrogen protection, heat up to 78 °C at a rate of 2 °C / min and stir for 30 min. Then synchronously dropwise add 2 / 3 weight of the pre-emulsion prepared in step (3) and 2 / 3 weight of the initiator solution prepared in step (4). After the dropping is completed, continue to stir for 3 h and cool to room temperature to obtain an antibacterial soybean oil acrylic emulsion. (6) Mix 500 g of antibacterial soybean oil acrylic emulsion and 75 g of waterborne curing agent (Covestro XP2655), stir at a speed of 300 rpm for 15 min, then add 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, and continue to stir for 30 min to obtain an environmentally friendly antibacterial coating. Example

[0029] (1) Add 18 g of epoxidized soybean oil to 60 g of acetone, heat up to 42 °C, dropwise add 10 g of hydrochloric acid aqueous solution with a concentration of 36 wt%, stir for 150 min, perform rotary evaporation, dissolve the product with ethyl acetate, and then wash it repeatedly with deionized water for 3 times. Take the organic layer and dry it under vacuum to obtain chlorinated epoxidized soybean oil; (2) Add 18 g of chlorinated epoxidized soybean oil, 7.5 g of dimethylaminoethyl methacrylate, and 6.2 g of 3-dimethylamino-1-propanol to 120 g of tetrahydrofuran. Under a nitrogen atmosphere, heat up to 52 °C and stir for 75 h. Perform rotary evaporation to obtain quaternary ammonium salt of alkenylated epoxidized soybean oil; (3) Add 4 g of sodium dodecyl sulfate and 2.4 g of alkylphenol polyoxyethylene ether OP-10 to 400 g of deionized water, heat up to 42 °C, and sequentially add 50 g of lauryl methacrylate, 35 g of butyl acrylate, 28 g of 2-hydroxyethyl methacrylate, and 18 g of quaternary ammonium salt of alkenylated epoxidized soybean oil. Stir at a speed of 1300 rpm for 30 min to obtain a pre-emulsion; (4) Add 4.8 g of ammonium persulfate to 57 g of deionized water and stir for 20 min to obtain an initiator solution; (5) Mix 1 / 3 weight of the pre-emulsion prepared in step (3) and 1 / 3 weight of the initiator solution prepared in step (4). Under nitrogen protection, heat up to 80 °C at a rate of 3 °C / min, stir for 40 min, and then simultaneously dropwise add 2 / 3 weight of the pre-emulsion prepared in step (3) and 2 / 3 weight of the initiator solution prepared in step (4). After the dropping is completed, continue to stir for 3.5 h and cool to room temperature to obtain an antibacterial soybean oil acrylate emulsion; (6) Mix 600 g of antibacterial soybean oil acrylate emulsion and 90 g of waterborne curing agent (Covestro XP2655), stir at a speed of 400 rpm for 20 min, then add 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, and continue to stir for 40 min to obtain an environmentally friendly antibacterial coating.

[0030] Comparative Example 1: The difference between Comparative Example 1 and Example 2 is that the quaternary ammonium salt of alkenylated epoxidized soybean oil in step (3) is replaced with epoxidized soybean oil; Comparative Example 2: The difference between Comparative Example 2 and Example 2 is that dimethylaminoethyl methacrylate in step (2) is replaced with an equimolar amount of 3-dimethylamino-1-propanol; Comparative Example 3: The difference between Comparative Example 3 and Example 2 is that 3-dimethylamino-1-propanol in step (2) is replaced with an equimolar amount of dimethylaminoethyl methacrylate; Comparative Example 4: The difference between Comparative Example 4 and Example 2 is that the dimethylaminoethyl methacrylate and 3-dimethylamino-1-propanol in step (2) are replaced by an equal molar amount of dodecyltrimethylammonium chloride; Performance Test: 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, and the coating thickness was controlled at (50±5) μm. After curing at room temperature for 7 days, a test piece was made. A sterile pipette was used to evenly drop 0.2 mL of bacterial suspension (concentration 1×10 5 CFU / mL), covered with sterile polyethylene film and placed in a constant temperature and humidity chamber (temperature 37℃±1℃, relative humidity RH≥90%) for 24 hours. The surface of the specimen was rinsed with physiological saline containing a neutralizer, inoculated onto a nutrient agar plate after gradient dilution, and colonies were counted after culturing at 37℃ for 48 hours. The antibacterial rate was calculated according to the formula: antibacterial rate (%) = (number of colonies in the blank control group - number of colonies in the sample group) / number of colonies in the blank control group × 100%. The results are shown in Table 1.

[0031] Antibacterial durability test: The coating sample was evenly coated on a sterile glass substrate, and the coating thickness was controlled at (50±5)μm. After curing at room temperature for 7 days, a test piece was made. The sample was placed in a xenon lamp aging box (irradiation intensity 0.55W / m², circulating spray deionized water) for 200 hours of accelerated aging, and the antibacterial performance test process was repeated to test the antibacterial rate. The results are shown in Table 1.

[0032] Mechanical properties test: According to GB / T 1720-2020, a coating with a dry film thickness of (25±2) μm was prepared on a standard tinplate using a film preparation device. After curing at room temperature for 7 days, a 1 mm × 1 mm grid array was drawn with a crosshair cutter, and a peel test was performed using 3M tape to test adhesion. The results are shown in Table 1. According to GB / T 6739-2006, a scratch test was performed using 13 grades of Zhonghua brand high-grade drawing pencils from 6B to 6H to test hardness. The results are shown in Table 1. According to GB / T 1732-2020, a QCJ impact tester was used to drop a 1 kg hammer from a height of 50 cm to impact the test plate, and the coating was observed for cracks, wrinkles and peeling. If no cracks, wrinkles or peeling were observed, the test was repeated at higher positions until cracks, wrinkles and peeling were observed. The height increased by 5 cm or multiples of 5 cm each time. If cracks, wrinkles and peeling are observed, the test is repeated at lower positions until no cracks, wrinkles and peeling are observed, and the height of each descent is 5 cm or multiples of 5 cm. The results are shown in Table 1.

[0033] Table 1 Performance Test Results Bacteriostatic rate / % Bacteriostatic 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 Data Analysis: 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 effects, and can maintain excellent antibacterial and mechanical properties in an aging environment. This indicates that the combination of the material formula and the preparation process effectively modifies the structure of the coatings, enabling them to not only possess initial antibacterial activity but also maintain stable functions under aging conditions. This may be attributed to the introduction of alkenylated epoxidized soybean oil quaternary ammonium salt in the formula, which can form a firm bond with the coating substrate and endow the surface with durable antibacterial properties without significantly affecting the mechanical strength of the coating. This optimized combination design makes the coating suitable for long-term applications and maintain good performance in harsh environments, showing significant advantages from the perspective of practical applications.

[0034] As can be seen from the data of Example 2 and Comparative Example 1 in Table 1, Example 2 has significant advantages over Comparative Example 1 in terms of antibacterial performance, antibacterial performance after aging, adhesion, and hardness. This modification effect may stem from the use of alkenylated epoxidized soybean oil quaternary ammonium salt, which not only provides high molecular activity but also significantly enhances the antibacterial effect of the coating at the molecular level through its unique quaternary ammonium salt functional groups.

[0035] As can be seen from the data of Example 2 and Comparative Example 2 in Table 1, the coatings of Example 2 show more excellent performance in terms of antibacterial stability after aging and mechanical properties such as hardness and adhesion. This may be attributed to the introduction of dimethylaminoethyl methacrylate, whose double bond structure can participate in copolymerization reactions to form a graft cross-linked network, not only improving the mechanical stability of the coating but also reducing the erosion of the external environment through a denser structure, thereby endowing the material with better anti-aging performance.

[0036] As can be seen from the data of Example 2 and Comparative Example 3 in Table 1, Example 2 is superior to Comparative Example 3 in terms of antibacterial performance, hardness, etc. This may be because the hydroxyl group of 3-dimethylamino-1-propanol may endow the alkenylated epoxidized soybean oil quaternary ammonium salt with stronger hydrophilicity, prompting this component to preferentially distribute on the surface of latex particles during the copolymerization process rather than being embedded inside the latex particles. Further, this makes the distribution density of quaternary ammonium salt on the coating surface higher, not only directly enhancing the contact efficiency between the antibacterial groups and bacteria but also stably anchoring the quaternary ammonium salt on the coating surface through curing cross-linking, avoiding the migration loss of antibacterial components during the aging process. In addition, the hydroxyl group may react with the waterborne curing agent as a cross-linking site, further enhancing the interfacial bonding force and coating hardness, thus showing a synergistic optimization effect in mechanical properties such as adhesion and impact resistance.

[0037] From the data of Example 2 and Comparative Example 4 in Table 1, it can be seen that compared with the direct addition of quaternary ammonium salts, the alkenylated epoxy soybean oil quaternary ammonium salt provided by the present invention further improves the antibacterial performance, adhesion and impact resistance after the coating ages. This is mainly because dodecyl trimethyl ammonium chloride is prone to migrate in the coating and is likely to fall off from the coating surface during the aging and scouring process.

[0038] Those of ordinary skill in the art should understand that the discussion of any above embodiment is only exemplary and is not intended to imply that the scope of the present invention is limited to these examples; under the concept of the present invention, the technical features in the above embodiments or different embodiments can also be combined, the steps can be implemented in any order, and there are many other variations in different aspects of the present invention as described above, which are not provided in detail for the sake of brevity.

Claims

1. An environmentally friendly antibacterial coating, characterized in that: The invention 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; 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 a nitrogen atmosphere, stir and react for 70-75 hours, and perform rotary evaporation to obtain olefinated epoxy soybean oil quaternary ammonium salt; (3) Using lauryl methacrylate, butyl acrylate, hydroxyethyl methacrylate and olefinated 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., dropping a hydrochloric acid aqueous solution, 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; 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 into deionized water, raise the temperature to 38-42°C, add the polymerization monomer, and stir at a speed of 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 min 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 20-40min, 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 2.5-3.5h, cool to room temperature, and obtain an antibacterial soybean oil acrylic emulsion.

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