Long-acting antibacterial mildew-proof plastic tablecloth and preparation method thereof

Abstract

The invention belongs to the technical field of tablecloth, and particularly relates to long-acting antibacterial mildew-proof plastic tablecloth and a preparation method thereof. The long-acting antibacterial mildew-proof plastic tablecloth is prepared from the following raw materials in parts by mass: 100 parts of PVC resin, 38 to 42 parts of plasticizer, 4 to 7 parts of flexibilizer, 3 to 5 parts of modified epoxidized soybean oil, 2 to 4 parts of stabilizer, 1 to 2 parts of pigment, 1 to 3 parts of processing aid and 6 to 8 parts of plastic antibacterial mildew-proof master batch. The plastic tablecloth disclosed by the invention has high tensile strength, high bending strength and high bending modulus of the plastic tablecloth and also has a good antibacterial effect.

Description

Technical Field

[0001] This invention belongs to the field of tablecloth technology, specifically relating to a long-lasting antibacterial and mildew-resistant plastic tablecloth and its preparation method. Background Technology

[0002] PVC (polyvinyl chloride) plastic tablecloths have become the most widely used tablecloth category in various scenarios such as homes, restaurants, offices, and kindergartens due to their unique advantages such as lightweight, easy processing and molding, corrosion resistance, water and oil resistance, low cost and convenient installation. They are an indispensable decorative and protective product in daily life and public environments.

[0003] Chinese patent CN112679883B discloses a PVC film material and its preparation method. By adding a toughening agent and continuously adjusting the raw material ratio, the problem of decreased toughness caused by thinning of the PVC film material is overcome. The PVC film material of this invention has a wide range of applications and can be used for tablecloth surface coverings. However, with the improvement of people's living standards and the continuous enhancement of health awareness, consumers' demands for the safety and functionality of PVC tablecloths are constantly increasing. Among them, antibacterial and antifungal properties have become a core requirement beyond basic performance, but the aforementioned tablecloths do not have antibacterial effects.

[0004] Shanghai Songya Chemical Co., Ltd.'s antibacterial (antimicrobial and antifungal) masterbatch possesses stable and long-lasting chemical properties, meets relevant non-toxic testing requirements, and boasts advantages such as broad-spectrum activity, durability, and resistance to discoloration. It provides excellent modification and protection for resin substrates, with minimal impact on the mechanical properties of the finished product, making it suitable for producing PVC products requiring antibacterial (antimicrobial and antifungal) functionality. However, research has found that adding the aforementioned particles to the PVC system affects the mechanical properties of PVC products. As a practical decorative item, the mechanical properties of PVC tablecloths directly determine the user experience and lifespan. Tensile strength, flexural strength, and flexural modulus are core indicators for evaluating the mechanical properties of PVC tablecloths, collectively determining their practicality, durability, and ease of use. Furthermore, the antibacterial properties of the antibacterial masterbatch are highly dependent on its microscopic dispersion state in the final product.

[0005] In summary, tensile strength, flexural strength, and flexural modulus are the three core mechanical properties of PVC tablecloths, and their performance directly determines the service life, user experience, and safety of PVC tablecloths. Meanwhile, antibacterial and anti-mildew properties are key functional indicators for meeting the health needs of modern consumers and expanding the high-end application scenarios of PVC tablecloths. Both must be considered to achieve a balance between the practical and functional value of PVC tablecloths. Summary of the Invention

[0006] The purpose of this invention is to provide a long-lasting antibacterial and mildew-resistant plastic tablecloth and its preparation method, which can take into account the excellent tensile strength, flexural strength, flexural modulus and antibacterial effect of the plastic tablecloth.

[0007] To achieve the above objectives, the present invention provides the following technical solution: A long-lasting antibacterial and mildew-proof plastic tablecloth comprises the following raw materials in parts by weight: 100 parts PVC resin, 38-42 parts plasticizer, 4-7 parts toughening agent, 3-5 parts modified epoxidized soybean oil, 2-4 parts stabilizer, 1-2 parts pigment, 1-3 parts processing aid, and 6-8 parts plastic antibacterial and mildew-proof masterbatch.

[0008] Preferably, the plasticizer includes phthalate plasticizers, bio-based plasticizer KE-7800, and bio-based plasticizer KE-3050.

[0009] Preferably, the plasticizer includes phthalate plasticizers in a mass ratio of 1:(0.7-0.8):(0.3-0.4), bio-based plasticizer of type KE-7800, and bio-based plasticizer of type KE-3050.

[0010] Adding antibacterial and antifungal masterbatch to traditional PVC tablecloths can give them antibacterial and antifungal properties, but it reduces the tablecloth's tensile strength. The addition of rigid particles like the antibacterial and antifungal masterbatch disrupts the continuity of the PVC molecular chains, creating stress concentration points under load and thus lowering tensile strength. This invention improves tensile strength by using a compounded plasticizer. Analysis shows that the plasticizer molecules insert into the PVC chains, increasing the mobility of the chain segments and improving the material's flexibility and ductility. Furthermore, it was found that when the plasticizers are compounded in a specific ratio, the antibacterial effect can be further improved. Analysis shows that under these optimized conditions, the dispersion and compatibility between raw materials are higher, and the distribution of the antibacterial and antifungal masterbatch is more uniform, thus ensuring the effective exposure and continuous release of antibacterial components while restoring the material's toughness.

[0011] Preferably, the toughening agent includes toughening agent of type MB885 and toughening agent of type KY-66.

[0012] Preferably, the toughening agent includes toughening agent MB885 and toughening agent KY-66 in a mass ratio of 1:(0.4-0.6).

[0013] The tablecloth's flexural strength is not ideal when using existing toughening agents in the system of this invention. The inventors improved the flexural strength by using a specific ratio of toughening agents MB885 and KY-66. This is because these two toughening agents form an effective synergistic toughening and stress transfer network within the PVC matrix, constructing a multi-layered, multi-mechanism energy dissipation network. By optimizing the interface and phase structure, the uniformity of stress transmission within the material is greatly improved, thus significantly enhancing the material's resistance to flexural failure.

[0014] Preferably, the modified epoxidized soybean oil is acetylated epoxidized soybean oil.

[0015] Preferably, the preparation method of the acetic anhydride acetylated modified epoxidized soybean oil includes the following steps: Step 1: Mix epoxidized soybean oil and sodium acetate, heat to obtain a preheated system; Step 2: Add acetic anhydride dropwise to the preheated system. After the addition is complete, maintain the temperature for the reaction. Step 3: After the reaction is complete, the system temperature is lowered to room temperature, and the system is distilled under reduced pressure. After distillation, sodium acetate is removed to obtain modified epoxidized soybean oil.

[0016] Preferably, the amount of acetic anhydride used accounts for 8-12% of the mass of epoxidized soybean oil.

[0017] Preferably, the conditions for the heat preservation reaction are: heat preservation reaction at 110-120℃ for 2-4 hours.

[0018] This invention significantly improves the flexural modulus of tablecloths by acetylation modification of epoxidized soybean oil, resulting in a crisper, more aesthetically pleasing, and textured appearance. Analysis shows that the grafting of acetyl groups onto the epoxidized soybean oil molecular chain enhances its compatibility with polar PVC molecular chains and intermolecular forces, moderately increasing the molecular rigidity and volume effect of the modified product while avoiding excessive cross-linking. This significant improvement in the material's flexural modulus gives the tablecloth better stiffness and resistance to deformation.

[0019] The preparation method of the long-lasting antibacterial and mildew-resistant plastic tablecloth includes the following steps: Step (1): Mix all raw materials to obtain a premix.

[0020] Step (2): Plasticize and extrude the premixed material to obtain granules; Step (3): The rubber granules are fed to a four-roll calender to form sheets; Step (4): Cool and shape the sheet and roll it up to obtain the finished long-lasting antibacterial and mildew-proof plastic tablecloth.

[0021] Compared with the prior art, the advantages and beneficial effects of the present invention are as follows: 1. The present invention adds plastic antibacterial and mildew-resistant masterbatch to PVC-based tablecloths, which can make the tablecloths have antibacterial and mildew-resistant effects.

[0022] 2. The present invention can improve tensile strength by adding compound plasticizers. When the plasticizers are compounded in a specific ratio, the antibacterial effect can be further improved.

[0023] 3. The present invention can improve the bending strength of tablecloths by using toughening agent of model MB885 and toughening agent of model KY-66 in a specific ratio.

[0024] 4. This invention can significantly improve the flexural modulus of tablecloths by acetylation modification of epoxidized soybean oil. In particular, when the amount of acetic anhydride accounts for 8-12% of the mass of epoxidized soybean oil, the flexural modulus can be improved and stabilized within the ideal performance range. Detailed Implementation

[0025] The technical solutions in the embodiments of the present invention will be clearly and completely described below. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0026] All raw materials used in the following embodiments of the present invention are commercially available products: Plastic antibacterial and mildew-proof masterbatch: from Shanghai Songya Chemical Co., Ltd., model: plastic antibacterial (antibacterial and mildew-proof) masterbatch.

[0027] The toughening agent MB885 is from the brand LGchem and distributed by Shanghai Yisheng Chemical Co., Ltd. MB885 is a methyl methacrylate-butadiene-styrene terpolymer produced by LG Corporation of South Korea; it is a core-shell structure impact modifier.

[0028] The toughening agent KY-66 comes from Shanghai Kunrui Chemical Co., Ltd. KY-66 is an environmentally friendly mixed modifier suitable for all PVC production processes and can be used in conjunction with traditional plasticizers.

[0029] Phthalate plasticizer: Diisononyl phthalate. Shanghai Kunrui Chemical Co., Ltd.

[0030] KE-7800 is a novel bio-based plasticizer synthesized from glycerol acetate and fatty acid esters (an ester of lauric acid and hydroxymalonyl diacetate). It is produced by Shanghai Kunrui Chemical Co., Ltd.

[0031] KE-3050 is a novel bio-based plasticizer synthesized from glycerol acetate and fatty acid esters (esters of fatty acids and hydroxypropane diacetate). It is sourced from Shanghai Kunrui Chemical Co., Ltd.

[0032] Viscosity reducer: Model: Viscosity reducer D70, Shanghai Rongfu New Energy Technology Co., Ltd.

[0033] PVC: Model SG-5, Shanghai Kunrui Chemical Co., Ltd.

[0034] Processing aid, model ACR processing aid, Shandong Ruifeng Polymer Materials Co., Ltd.

[0035] Calcium-zinc stabilizer, CZ-70, Jining Tangyi Chemical Co., Ltd.

[0036] Epoxidized soybean oil: Shanghai Kunrui Chemical Co., Ltd.

[0037] Pigment: Ultramarine. Example

[0038] This embodiment provides a long-lasting antibacterial and mildew-proof plastic tablecloth, comprising the following raw materials in parts by weight: 100 parts PVC resin, 40 parts plasticizer, 5 parts toughening agent, 3 parts modified epoxidized soybean oil, 3 parts calcium-zinc stabilizer, 1 part pigment, 2 parts processing aid, and 6.5 parts plastic antibacterial and mildew-proof masterbatch.

[0039] The plasticizers include diisononyl phthalate in a mass ratio of 1:0.8:0.3, bio-based plasticizer KE-7800, and bio-based plasticizer KE-3050.

[0040] The toughening agents include toughening agent MB885 (mass ratio 1:0.5) and toughening agent KY-66.

[0041] The preparation method of the modified epoxidized soybean oil includes the following steps: Step 1: Mix 100 parts by weight of epoxidized soybean oil and 2 parts by weight of sodium acetate, heat to 105°C under stirring at 300 rpm, mix for 15 minutes to obtain a preheated system; Step 2: Add 12 parts by mass of acetic anhydride to the preheated system over a period of 50 minutes. After the addition is complete, keep the system at 120°C for 2 hours. During this process, the acetic anhydride reacts with the hydroxyl groups in the epoxidized soybean oil to undergo acetylation.

[0042] Step 3: After the reaction is complete, the system temperature is lowered to room temperature, and then distilled for 60 minutes at 80℃ and a vacuum of -0.095MPa to remove the reaction byproduct acetic acid and unreacted acetic anhydride. After distillation, the solid catalyst sodium acetate is removed by hot filtration to obtain modified epoxidized soybean oil.

[0043] The preparation method of the above-mentioned long-lasting antibacterial and mildew-resistant plastic tablecloth includes the following steps: Step (1): Raw material premixing: Put all raw materials into a high-speed hot mixer and dry mix them for 1.5 minutes at a speed of 250 rpm. Increase the speed to 950 rpm and start heating. When the material temperature reaches 115℃, immediately unload the material into a low-speed cold mixer and stir and cool it at a speed of 120 rpm in the cold mixer. When the material temperature drops to room temperature, discharge the material to obtain the premix.

[0044] Step (2): Plasticizing extrusion granulation: Plasticizing extrusion is performed using a co-rotating parallel twin-screw extruder. The temperature settings for each section are as follows: C1 (feeding section): 125℃; C2 / C3 (melting / compression section): 155℃ / 165℃; C4 / C5 / C6 (homogenization / metering section): 168℃ / 170℃ / 165℃; Die head section: 160℃; The twin-screw speed is 380rpm, and the die head pressure is controlled at 20MPa. After hot cutting through the die surface, granules are obtained.

[0045] Step (3): Calendering: The rubber granules are fed into a four-roll calender for forming. The temperatures of each roll are set as follows: Roll 1 (upper roll): 195℃; Roll 2 (middle upper roll): 205℃; Roll 3 (middle lower roll): 185℃ Roll 4 (lower roll): 178℃; Linear speed settings for each roll: Roll 1: 15m / min; Roll 2: 25m / min; Roll 3: 30m / min; Roll 4: 35m / min; Roll gap settings for each roll: Roll 1 (heating side / drive side): 1.20mm / 1.25mm; Roll 2 (heating side / drive side): 1.00mm / 0.95mm; Roll 3 (heating side / drive side): 0.90mm / 0.82mm; Roll 4 (heating side / drive side): 6.20mm / 6.18mm. After calendering, a sheet is obtained. Step (4): Cooling, shaping, and winding; the sheet is drawn from the calender by traction rollers at a temperature of 170℃ and a traction roller speed of 180m / min; then it enters the cooling roller group: the surface temperature of the first cooling roller (cooling section) is 15℃; the surface temperature of the second cooling roller (normal temperature shaping section) is 22℃. The linear speed of the cooling roller is 235m / min; then it passes through the embossing roller at a speed of 225m / min and a pressure of 0.5MPa, and finally is wound up by the winding machine at a speed of 245m / min to obtain the finished long-lasting antibacterial and mildew-proof plastic tablecloth. Example

[0046] This embodiment provides a long-lasting antibacterial and mildew-proof plastic tablecloth, comprising the following raw materials in parts by weight: 100 parts PVC resin, 42 parts plasticizer, 4 parts toughening agent, 5 parts modified epoxidized soybean oil, 2 parts stabilizer, 1 part pigment, 3 parts processing aid, and 8 parts plastic antibacterial and mildew-proof masterbatch.

[0047] The plasticizers include diisononyl phthalate in a mass ratio of 1:0.7:0.4, bio-based plasticizer KE-7800, and bio-based plasticizer KE-3050.

[0048] The toughening agents include toughening agent MB885 (mass ratio 1:0.6) and toughening agent KY-66.

[0049] The preparation method of the modified epoxidized soybean oil includes the following steps: Step 1: Mix 100 parts by weight of epoxidized soybean oil and 3 parts by weight of sodium acetate, heat to 110°C under stirring at 300 rpm, mix for 10 minutes to obtain a preheated system; Step 2: Add 10 parts by mass of acetic anhydride to the preheated system over a period of 50 minutes. After the addition is complete, keep the system at 115°C for 3 hours. During this process, the acetic anhydride reacts with the hydroxyl groups in the epoxidized soybean oil to undergo an acetylation reaction.

[0050] Step 3: After the reaction is complete, the system temperature is lowered to room temperature, and then distilled for 60 minutes at 80℃ and a vacuum of -0.095MPa to remove the reaction byproduct acetic acid and unreacted acetic anhydride. After distillation, the solid catalyst sodium acetate is removed by hot filtration to obtain modified epoxidized soybean oil.

[0051] The preparation method of the above-mentioned long-lasting antibacterial and mildew-resistant plastic tablecloth includes the following steps: Step (1): Raw material premixing: Put all raw materials into a high-speed hot mixer and dry mix them for 1.5 minutes at a speed of 250 rpm. Increase the speed to 950 rpm and start heating. When the material temperature reaches 115℃, immediately unload the material into a low-speed cold mixer and stir and cool it at a speed of 120 rpm in the cold mixer. When the material temperature drops to room temperature, discharge the material to obtain the premix.

[0052] Step (2): Plasticizing extrusion granulation: Plasticizing extrusion is performed using a co-rotating parallel twin-screw extruder. The temperature settings for each section are as follows: C1 (feeding section): 125℃; C2 / C3 (melting / compression section): 155℃ / 165℃; C4 / C5 / C6 (homogenization / metering section): 168℃ / 170℃ / 165℃; Die head section: 160℃; The twin-screw speed is 380rpm, and the die head pressure is controlled at 20MPa. After hot cutting through the die surface, granules are obtained.

[0053] Step (3): Calendering: The rubber granules are fed into a four-roll calender for forming. The temperatures of each roll are set as follows: Roll 1 (upper roll): 195℃; Roll 2 (middle upper roll): 205℃; Roll 3 (middle lower roll): 185℃ Roll 4 (lower roll): 178℃; Linear speed settings for each roll: Roll 1: 15m / min; Roll 2: 25m / min; Roll 3: 30m / min; Roll 4: 35m / min; Roll gap settings for each roll: Roll 1 (heating side / drive side): 1.20mm / 1.25mm; Roll 2 (heating side / drive side): 1.00mm / 0.95mm; Roll 3 (heating side / drive side): 0.90mm / 0.82mm; Roll 4 (heating side / drive side): 6.20mm / 6.18mm. After calendering, a sheet is obtained. Step (4): Cooling, shaping, and winding; the sheet is drawn from the calender by traction rollers at a temperature of 170℃ and a traction roller speed of 180m / min; then it enters the cooling roller group: the surface temperature of the first cooling roller (cooling section) is 15℃; the surface temperature of the second cooling roller (normal temperature shaping section) is 22℃. The linear speed of the cooling roller is 235m / min; then it passes through the embossing roller at a speed of 225m / min and a pressure of 0.5MPa, and finally is wound up by the winding machine at a speed of 245m / min to obtain the finished long-lasting antibacterial and mildew-proof plastic tablecloth.

[0054] Comparative Example 1 The difference between this comparative example and Example 1 is that the plasticizers include diisononyl phthalate in a mass ratio of 1:0.5:0.5, bio-based plasticizers of type KE-7800 and type KE-3050.

[0055] Comparative Example 2 The difference between this comparative example and Example 1 is that the plasticizer includes diisononyl phthalate in a mass ratio of 1:0.8 and a bio-based plasticizer of type KE-7800.

[0056] Comparative Example 3 The difference between this comparative example and Example 1 is that the plasticizer is the plasticizer used in Chinese Patent CN112679883B, a PVC film material and its preparation method. Specifically, the plasticizer includes 24 parts by weight of DINP and 4 parts by weight of TXIB. The brand of DINP is Shanghai Kunrui Chemical Co., Ltd., and the brand of TXIB is Eastman Chemical Company.

[0057] Comparative Example 4 The difference between this comparative example and Example 1 is that the toughening agent includes toughening agent MB885 and toughening agent KY-66 in a mass ratio of 1:1.

[0058] Comparative Example 5 The difference between this comparative example and Example 1 is that the toughening agent is MB885.

[0059] Comparative Example 6 The difference between this comparative example and Example 1 is that the modified epoxidized soybean oil was replaced with epoxidized soybean oil (Shanghai Kunrui Chemical Co., Ltd.).

[0060] Comparative Example 7 The difference between this comparative example and Example 1 is that 6 parts by mass of acetic anhydride were added dropwise to the preheating system.

[0061] Comparative Example 8 The difference between this comparative example and Example 1 is that 14 parts by mass of acetic anhydride were added dropwise to the preheating system.

[0062] Performance testing Performance tests were conducted on the tablecloths of Examples 1-2 and Comparative Examples 1-8.

[0063] 1. Test the tensile strength according to ASTM D882.

[0064] 2. Test the bending strength according to ASTM D790.

[0065] 3. Test the flexural modulus according to ASTM D790.

[0066] 4. Antibacterial Properties: Cut the plastic tablecloth into 1 cm diameter round pieces as samples. Place the tablecloth sample round pieces in a sterile workbench for sterilization. Prepare Escherichia coli (concentration of 10) according to national standard GB / T31402-2023. 6 CFU / mL bacterial suspension. Take a 10 cm diameter nutrient agar plate and evenly spread 100 μL of the above bacterial suspension on its surface. Then, place the treated samples on the plate surface at intervals. Incubate at 35°C for 24 hours. Measure the diameter of the inhibition zone to determine the antibacterial performance.

[0067] The test results are shown in Table 1.

[0068] Table 1 Performance Test Results As shown in Table 1, the plastic tablecloths of Examples 1-2 have high antibacterial properties, tensile strength of 102-106 MPa, flexural strength of 130-134 MPa, and flexural modulus of 2013-2020 MPa. Their comprehensive mechanical properties are superior to the tensile strength, flexural strength, and flexural modulus of a PVC film material and its preparation method disclosed in Chinese Patent CN112679883B.

[0069] In Comparative Example 1, the change in the plasticizer ratio resulted in a decrease in both antibacterial effect and mechanical properties. This was attributed to the disruption of the synergistic dispersion effect of the system, leading to a decrease in the uniformity of the antibacterial masterbatch dispersion and the homogeneity of the material.

[0070] In Comparative Example 2, the lack of KE-3050 bio-based plasticizer resulted in a decrease in antibacterial effect and mechanical properties. Analysis showed that the reduced polarity of the plasticizer system and its compatibility with the components affected the dispersibility of the antibacterial masterbatch.

[0071] In Comparative Example 3, the traditional DINP / TXIB plasticizing system was used, which resulted in a decrease in antibacterial effect and mechanical properties. This was attributed to the loss of the compatibility-promoting and uniform dispersion-enhancing functions unique to the KE series of bio-based plasticizers, and a reduction in compatibility with the components.

[0072] In Comparative Example 4, the toughening agent ratio was changed, and the bending strength decreased. The analysis showed that the energy dissipation synergy network between MB885 and KY-66 was disrupted, resulting in a decrease in stress transfer efficiency.

[0073] In Comparative Example 5, only MB885 toughening agent was used, and the bending strength was significantly insufficient. The analysis showed that the lack of synergy of the KY-66 elastomer phase made it difficult to construct a multi-level energy dissipation network, thus weakening the material's ability to resist bending failure.

[0074] In Comparative Example 6, unmodified epoxidized soybean oil was used, resulting in a significant decrease in flexural modulus. Analysis suggests that ordinary epoxidized soybean oil molecules have weak polarity and insufficient rigidity, leading to poor compatibility with the system and an inability to provide enhanced interfacial bonding and rigid support.

[0075] In Comparative Example 7, the amount of acetic anhydride was insufficient, resulting in a decrease in flexural modulus. The analysis indicated that the degree of acetylation reaction was low, failing to introduce a sufficient number of rigid acetyl groups into the epoxidized soybean oil molecular chain, thus having a weak effect on restricting the movement of the PVC molecular chain.

[0076] In Comparative Example 8, the amount of acetic anhydride was too high, resulting in a decrease in both the overall mechanical properties and the antibacterial effect. The analysis suggests that excessive modification may lead to the loss of epoxy groups and excessive product viscosity, which in turn impairs the compatibility with the PVC matrix and the processing and dispersibility.

[0077] The above description represents the preferred embodiments of the present invention. It should be noted that those skilled in the art can make various improvements and modifications without departing from the principles of the present invention, and these improvements and modifications should also be considered within the scope of protection of the present invention.

Claims

1. A long-lasting antibacterial and mildew-resistant plastic tablecloth, characterized in that, The raw materials include the following parts by weight: 100 parts PVC resin, 38-42 parts plasticizer, 4-7 parts toughening agent, 3-5 parts modified epoxidized soybean oil, 2-4 parts stabilizer, 1-2 parts pigment, 1-3 parts processing aid, and 6-8 parts plastic antibacterial and antifungal masterbatch.

2. The long-lasting antibacterial and mildew-resistant plastic tablecloth according to claim 1, characterized in that, Plasticizers include diisononyl phthalate, bio-based plasticizer KE-7800, and bio-based plasticizer KE-3050.

3. The long-lasting antibacterial and mildew-resistant plastic tablecloth according to claim 2, characterized in that, Plasticizers include diisononyl phthalate in a mass ratio of 1:(0.7-0.8):(0.3-0.4), bio-based plasticizer KE-7800, and bio-based plasticizer KE-3050.

4. The long-lasting antibacterial and mildew-resistant plastic tablecloth according to claim 1, characterized in that, The toughening agents include toughening agent MB885 and toughening agent KY-66.

5. The long-lasting antibacterial and mildew-resistant plastic tablecloth according to claim 4, characterized in that, The toughening agents include toughening agent MB885 with a mass ratio of 1:(0.4-0.6) and toughening agent KY-66.

6. The long-lasting antibacterial and mildew-resistant plastic tablecloth according to claim 1, characterized in that, The modified epoxidized soybean oil is acetylated epoxidized soybean oil with acetic anhydride.

7. The long-lasting antibacterial and mildew-resistant plastic tablecloth according to claim 6, characterized in that, The preparation method of the acetic anhydride acetylated modified epoxidized soybean oil includes the following steps: Step 1: Mix epoxidized soybean oil and sodium acetate, heat to obtain a preheated system; Step 2: Add acetic anhydride dropwise to the preheated system. After the addition is complete, maintain the temperature for the reaction. Step 3: After the reaction is complete, the system temperature is lowered to room temperature, and the system is distilled under reduced pressure. After distillation, sodium acetate is removed to obtain acetic anhydride acetylated modified epoxidized soybean oil.

8. The long-lasting antibacterial and mildew-resistant plastic tablecloth according to claim 7, characterized in that, Acetic anhydride accounts for 8-12% of the mass of epoxidized soybean oil.

9. The long-lasting antibacterial and mildew-resistant plastic tablecloth according to claim 7, characterized in that, The conditions for the heat preservation reaction are: heat preservation reaction at 110-120℃ for 2-4 hours.

10. A method for preparing a long-lasting antibacterial and mildew-resistant plastic tablecloth according to any one of claims 1-9, characterized in that, Includes the following steps: Step (1): Mix all raw materials to obtain a premix; Step (2): Plasticize and extrude the premixed material to obtain granules; Step (3): The rubber granules are fed to a four-roll calender to form sheets; Step (4): Cool and shape the sheet and roll it up to obtain the finished long-lasting antibacterial and mildew-proof plastic tablecloth.