Antibacterial PVC plate and preparation method thereof

Abstract

The invention provides an antibacterial PVC (polyvinyl chloride) plate and a preparation method thereof. The antibacterial PVC plate is prepared from the following raw materials: 95 to 105 parts of matrix resin, 6 to 14 parts of heat-resistant reinforcing agent, 1.5 to 4.5 parts of fluorine functional agent, 2 to 6 parts of multifunctional interface reinforcing agent, 1.5 to 5 parts of composite antibacterial agent, 1.3 to 4.5 parts of interface compatibilizer, 9 to 18 parts of filler, 2.5 to 4.5 parts of stabilizer, 1.3 to 3 parts of lubricant, 0.4 to 0.9 part of antioxidant and 0.3 to 0.8 part of ultraviolet light absorber. According to the antibacterial PVC plate, all the components have a synergistic effect, so that the antibacterial PVC plate has excellent antibacterial function and also has heat resistance, compatibility, processability, aging resistance and mechanical stability, and the use requirements of the antibacterial PVC plate are met.

Description

Technical Field

[0001] This invention relates to the field of PVC sheet technology, specifically to an antibacterial PVC sheet and its preparation method. Background Technology

[0002] Polyvinyl chloride (PVC) sheets are widely used in building decoration, home furnishings, and medical protective equipment due to their ease of processing and controllable cost. As demand for hygiene, safety, and durability increases, imbuing them with antibacterial properties and optimizing their overall performance has become a key research focus. In existing technologies, antibacterial PVC sheets are typically based on a matrix resin, combined with antibacterial components and auxiliary functional components (such as components that improve heat resistance, weather resistance, and mechanical properties). These components need to work synergistically to meet usage requirements, but the current synergistic effect between components still needs improvement.

[0003] While existing antibacterial PVC sheets can achieve initial antibacterial effects by adding antibacterial components and improve some basic properties with the help of auxiliary components, it is difficult to achieve an ideal balance between the core antibacterial durability and the key heat resistance (such as high-temperature deformation resistance) and mechanical stability in practical applications. Some products are prone to performance failure at high temperatures, and the antibacterial effect decays rapidly with the use time. In addition, the compatibility and dispersion uniformity between some components are insufficient, which further restricts the stable performance of the overall sheet and cannot meet the needs of long-term use in complex environments. Summary of the Invention

[0004] To address the problems existing in the prior art, the present invention provides an antibacterial PVC sheet and its preparation method.

[0005] To achieve the above objectives, the present invention provides the following technical solution: This application discloses an antibacterial PVC sheet, wherein the raw materials comprising the antibacterial PVC sheet by weight are: 95-105 parts of matrix resin, 6-14 parts of heat-resistant reinforcing agent, 1.5-4.5 parts of fluorine functional agent, 2-6 parts of multifunctional interface reinforcing agent, 1.5-5 parts of composite antibacterial agent, 1.3-4.5 parts of interface compatibilizer, 9-18 parts of filler, 2.5-4.5 parts of stabilizer, 1.3-3 parts of lubricant, 0.4-0.9 parts of antioxidant, and 0.3-0.8 parts of ultraviolet absorber.

[0006] By setting up the above technical solutions, the matrix resin serves as the basic carrier, providing support for the molding and basic mechanical properties of the board; the heat-resistant reinforcing agent can improve the board's resistance to high-temperature deformation and prevent board failure at high temperatures; the fluorinated functional agent can improve the surface properties and weather resistance of the board, extending its service life in outdoor or complex environments; the multifunctional interface reinforcing agent can optimize the interfacial bonding state between various components within the board, reducing interface defects; the composite antibacterial agent is the core component that gives the antibacterial PVC board its antibacterial function, enabling it to have antibacterial and bacteriostatic effects; the interface compatibilizer can improve the compatibility of the resin with other fillers and functional agents, ensuring uniform dispersion of each component; the filler can enhance the rigidity and dimensional stability of the board; the stabilizer can inhibit the degradation of PVC resin, maintaining the long-term stable performance of the board; the lubricant can improve the fluidity of the board during processing, preventing materials from sticking to equipment and ensuring smooth molding; the antioxidant can inhibit the thermo-oxidative aging of the board during processing and use, extending its service life; the ultraviolet absorber can absorb ultraviolet rays, reducing the damage of ultraviolet rays to the board structure and further improving the board's weather resistance. These components work synergistically to give antibacterial PVC sheets excellent antibacterial properties while also ensuring heat resistance, compatibility, processability, aging resistance, and mechanical stability, thus meeting their application requirements.

[0007] Preferably, the matrix resin is SG-5 type polyvinyl chloride resin; the heat-resistant reinforcing agent is composed of chlorinated polyvinyl chloride and polysulfone in a mass ratio of 0.8:1-4.5:1; the fluorine-based functional agent is polyvinylidene fluoride micro powder with a particle size of 0.5-2μm; the interface compatibilizer is composed of maleic anhydride-grafted ethylene-vinyl acetate copolymer with a grafting rate of 1.5%-3% and maleic anhydride-grafted polypropylene with a grafting rate of 2%-4% in a mass ratio of 0.4:1-5:1; the filler is composed of light calcium carbonate and nano silica in a mass ratio of 2.67:1-15:1, and the surface of the nano silica is modified by a silane coupling agent; the stabilizer is a calcium-zinc composite stabilizer doped with rare earth lanthanum ions; the lubricant is composed of pentaerythritol stearate and zinc stearate in a mass ratio of 0.67:1-3.6:1; the antioxidant is antioxidant 168; and the ultraviolet absorber is ultraviolet absorber UV-531.

[0008] By setting up the above technical solutions, SG-5 type polyvinyl chloride resin provides basic processing and mechanical support for antibacterial polyvinyl chloride sheets, and serves as a dispersion carrier for various functional components; the heat-resistant reinforcing agent composed of chlorinated polyvinyl chloride and polysulfone in a mass ratio of 0.8:1-4.5:1 can synergistically improve the sheet's resistance to high-temperature deformation and prevent sheet deformation at high temperatures; polyvinylidene fluoride micropowder with a particle size of 0.5-2μm, as a fluorine-based functional agent, can be uniformly dispersed in the matrix, reducing the surface energy of the sheet and enhancing weather resistance; the interface compatibilizer composed of maleic anhydride-grafted ethylene-vinyl acetate copolymer with a grafting rate of 1.5%-3% and maleic anhydride-grafted polypropylene with a grafting rate of 2%-4% in a mass ratio of 0.4:1-5:1 can synergistically improve the performance of the sheet through specific grafting rates and ratios. The interfacial bonding between resin and filler reduces internal defects; a filler composed of light calcium carbonate and nano-silica modified with silane coupling agent at a mass ratio of 2.67:1-15:1 can reduce costs and improve the rigidity of the board while enhancing dimensional stability with the help of modified nano-silica; a calcium-zinc composite stabilizer doped with rare earth lanthanum ions can effectively inhibit the degradation of polyvinyl chloride and ensure the stability of the board performance; a lubricant composed of pentaerythritol stearate and zinc stearate at a mass ratio of 0.67:1-3.6:1 can ensure smooth processing and a smooth surface of the board through synergistic internal and external lubrication; antioxidant 168 and ultraviolet absorber UV-531 inhibit thermo-oxidative aging and absorb ultraviolet rays, respectively, and together extend the service life of antibacterial polyvinyl chloride boards.

[0009] Preferably, the chlorine content of chlorinated polyvinyl chloride in the heat-resistant reinforcing agent is 63%-67%; the fineness of light calcium carbonate in the filler is 1250 mesh, and the particle size of nano silica is 50 nm; the content of rare earth lanthanum ions in the stabilizer is 2%-5%.

[0010] By implementing the above technical solutions, chlorinated polyvinyl chloride (PVC) can enhance the heat resistance of antibacterial PVC sheets by strengthening intermolecular polar forces, thus preventing deformation during high-temperature processing or use. The 1250-mesh fine calcium carbonate filler, with its small particle size and uniform distribution, can fully fill the gaps between resin molecular chains, reducing production costs while increasing rigidity and minimizing internal structural defects. The 50nm nano-silica, with its small particle size, is more compatible with the resin, inhibiting resin molecular chain creep, enhancing dimensional stability, and reducing thermal shrinkage. The 2%-5% rare earth lanthanum ions in the stabilizer help inhibit PVC degradation, ensuring stable long-term performance of the sheets.

[0011] Preferably, the raw materials of the multifunctional interface enhancer include: 4-6 parts of octavinyl-polyhedral oligomeric silsesquioxane, 8-12 parts of 1H,1H,2H,2H-perfluorooctyl mercaptan, 0.13-0.2 parts of azobisisobutyronitrile, and 95-105 parts of toluene.

[0012] By setting up the above technical solution, octavinyl-polyhedral oligomeric silsesquioxane, as the core skeleton material of the multifunctional interface reinforcing agent, can provide an inorganic-organic hybrid polyhedral cage structure, laying the foundation for subsequent nanoscale reinforcement of antibacterial PVC sheets; 1H,1H,2H,2H-perfluorooctyl mercaptan can introduce fluorocarbon chains into the interface reinforcing agent through reaction, enabling it to form good compatibility with fluorinated functional agents in antibacterial PVC sheets, thereby improving the interfacial bonding state of various components inside the sheet; azobisisobutyronitrile, as an initiator, can promote the full reaction of octavinyl-polyhedral oligomeric silsesquioxane and 1H,1H,2H,2H-perfluorooctyl mercaptan, ensuring the integrity of the interface reinforcing agent structure and the stability of its performance; toluene, as a solvent, can uniformly dissolve and mix the above raw materials, ensuring the smooth progress of the reaction. The multifunctional interface enhancer prepared from these raw materials can effectively improve the interfacial bonding force between the resin, filler, and antibacterial agent when applied to antibacterial polyvinyl chloride sheets, reduce interfacial defects, and at the same time help enhance the rigidity and heat resistance of the sheets. It can also help the antibacterial agent to be uniformly dispersed in the matrix, providing support for the synergistic optimization of the antibacterial and mechanical properties of the sheets.

[0013] Preferably, the preparation method of the multifunctional interface enhancer includes the following steps: 1) Select a 500mL dry three-necked flask, equip it with a stirrer, reflux condenser and nitrogen inlet tube, place the flask in a constant temperature water bath, add octavinyl-polyhedral oligomeric silsesquioxane and toluene to the three-necked flask, stir at 300-400r / min at room temperature for 30-40min until the octavinyl-polyhedral oligomeric silsesquioxane is completely dissolved and a transparent solution is formed; 2) Add 1H,1H,2H,2H-perfluorooctyl mercaptan and azobisisobutyronitrile sequentially to the transparent solution, and continue stirring at 300-400 r / min for 15-20 min to ensure uniform mixing. Then, purge the air in the flask three times at a rate of 100-150 mL / min, with each purge lasting 10 min. After the purge is complete, maintain the nitrogen pressure at 0.01-0.02 MPa, raise the temperature of the constant temperature water bath to 70-80℃ at 5℃ / min, turn on reflux, and react for 24-48 h. 3) After the reaction is complete, turn off the heating and stirring, cool the reaction solution to room temperature, and slowly drop the cooled reaction solution into 5 times the volume of the reaction solution in ice-cold methanol at 0-5℃. During this process, keep stirring at 200-300 r / min. After a white precipitate is formed, filter the precipitate using a Buchner funnel and wash it repeatedly with ice-cold methanol 3-5 times to remove unreacted 1H,1H,2H,2H-perfluorooctyl mercaptan and azobisisobutyronitrile. 4) Place the precipitate treated in step 3) in a vacuum oven, set the temperature to 50℃ and the vacuum degree to -0.095MPa to -0.098MPa, and dry for 24 hours to obtain a multifunctional interface enhancer.

[0014] By setting up the above technical solution, using a dry three-necked flask and purging with nitrogen for protection, the reaction can be prevented from being interfered with by impurities such as moisture and air, reducing the formation of by-products and ensuring that the reaction between octavinyl-polyhedral oligomeric silsesquioxane and 1H,1H,2H,2H-perfluorooctyl mercaptan is complete and the product structure is intact. Reasonable stirring speed and time allow the raw materials to be fully dissolved and mixed, and precise temperature control and reflux conditions promote stable reaction, ensuring the formation of a product with an inorganic-organic hybrid polyhedral cage structure. Cold methanol precipitation and repeated washing remove unreacted raw materials, and vacuum drying removes moisture and residual solvents, further improving the purity and stability of the product. The resulting multifunctional interface enhancer, when applied to antibacterial PVC sheets, can more effectively improve the interfacial bonding between the resin, filler, and antibacterial agent, reduce interfacial defects, and help improve the rigidity and heat resistance of the sheets. It also helps the antibacterial agent to be uniformly dispersed in the matrix, providing a guarantee for the optimization of the overall performance of the sheets.

[0015] Preferably, in step 2), samples need to be taken every 3 hours during the reflux reaction, and the characteristic peak of vinyl groups (1630 cm⁻¹) needs to be monitored by infrared spectroscopy. -1 To determine the reaction endpoint, observe the disappearance of the precipitate; in step 3), the amount of ice-cold methanol used to wash the precipitate each time is twice the wet weight of the precipitate.

[0016] By setting up the above technical solution, samples were taken every 3 hours during the reflux reaction, and the characteristic peak of vinyl groups (1630 cm⁻¹) was monitored by infrared spectroscopy. -1 The disappearance of these substances allows for precise judgment of the reaction progress between octavinyl-polyhedral oligomeric silsesquioxane and 1H,1H,2H,2H-perfluorooctyl mercaptan, ensuring a complete reaction and preventing incomplete product structure defects that could affect its interfacial strengthening function. During purification, each wash with twice the wet weight of the precipitate in ice-cold methanol provides sufficient solvent to thoroughly remove unreacted 1H,1H,2H,2H-perfluorooctyl mercaptan and azobisisobutyronitrile, guaranteeing product purity. The resulting high-purity, structurally complete, multifunctional interfacial reinforcing agent, when applied to antibacterial PVC sheets, can more effectively improve the interfacial bonding between the resin, filler, and antibacterial agent, reducing interfacial defects and providing support for the stable improvement of the sheet's mechanical and heat resistance properties.

[0017] Preferably, the raw materials of the composite antibacterial agent, by weight, include: 0.8-1.2 parts graphene oxide, 95-105 parts deionized water, 2-4 parts silver nitrate, 0.8-1.6 parts sodium borohydride, 2-4 parts zinc nitrate, 10-15 parts ammonia water with a mass concentration of 25%-28%, and 48-52 parts ethanol.

[0018] By setting up the above technical solution, graphene oxide, as the carrier of the composite antibacterial agent, can effectively load silver nanoparticles and zinc oxide due to its high specific surface area, laying the foundation for the uniform dispersion of antibacterial components in the antibacterial PVC board and avoiding the impact of agglomeration on the antibacterial effect. Deionized water, as a solvent, can fully dissolve raw materials such as graphene oxide and silver nitrate to form a uniform dispersion, ensuring the smooth progress of each reaction step. Silver nitrate is the source of silver ions, which can destroy bacterial cell membranes and are the core component for achieving rapid antibacterial action in the board. Sodium borohydride can reduce silver ions to silver nanoparticles, enhance the antibacterial activity of silver, and further enhance the antibacterial efficiency of the board. Zinc nitrate is the source of zinc and can be converted into zinc oxide. Zinc oxide can generate active oxygen under light, which works synergistically with silver ions to achieve long-lasting antibacterial action in the board. Ammonia water with a mass concentration of 25%-28% can adjust the pH value of the reaction system, helping to generate uniform zinc hydroxide and convert it into a zinc oxide shell, ensuring the structural stability of the antibacterial agent. Ethanol can be used to wash the antibacterial agent, remove residual impurities and moisture, and improve the purity of the antibacterial agent. When the composite antibacterial agent prepared from these raw materials is applied to antibacterial polyvinyl chloride (PVC) sheets, it can impart efficient, long-lasting and uniform antibacterial properties to the sheets, while its stable structure is not likely to have a negative impact on the mechanical properties of the sheets.

[0019] Preferably, the preparation method of the compound antibacterial agent includes the following steps: a. Dissolve silver nitrate, sodium borohydride, and zinc nitrate separately in deionized water to prepare solutions with concentrations of 0.1-0.3 mol / L, 0.09-0.11 mol / L, and 0.2-0.5 mol / L, respectively; b. Add graphene oxide to deionized water and place it in an ultrasonic disperser. Set the power to 300-500W and the ultrasonic time to 30-60min. Stop the machine for 5min every 15min during the process. After the ultrasonication is completed, a graphene oxide dispersion is obtained. c. Transfer the graphene oxide dispersion to a 250 mL three-necked flask and stir at 250-300 r / min at room temperature. Add silver nitrate solution dropwise at a uniform rate over 15-20 min. After the addition is complete, continue stirring for 30 min. Then, add sodium borohydride solution dropwise at a uniform rate over 20-30 min. After the addition is complete, react at room temperature for 1-2 h to obtain a silver / graphene oxide dispersion. d. Add zinc nitrate solution to the silver / graphene oxide dispersion and stir for 10-15 min. Add ammonia water at a dropping rate of 1-2 mL / min to adjust the pH of the solution to 8-9. Then, place the three-necked flask in a constant temperature water bath, heat to 60-80℃, stir at 200-250 r / min for 2-4 h, and then heat to 100-120℃ and keep warm for 1-2 h. e. Transfer the dispersion obtained in step d to a centrifuge tube and place it in a high-speed centrifuge. Set the rotation speed to 8000-10000 r / min and the centrifugation time to 10-15 min. Collect the precipitate and wash it with deionized water 3-4 times until the pH of the washing solution is 7. Then wash it once with ethanol to remove residual water on the surface. Finally, place the washed precipitate in a vacuum oven and set the temperature to 50-60℃ and the vacuum degree to -0.095MPa to -0.098MPa. Dry it for 12-24 h and then pulverize it with a planetary ball mill and pass it through a 200-mesh sieve to obtain the composite antibacterial agent. Each time the product is washed with deionized water, it needs to be centrifuged at 4900-5000 r / min for 5 min.

[0020] By setting up the above technical solution, silver nitrate, sodium borohydride, and zinc nitrate are prepared into solutions of specific concentrations, which ensures the precise concentration of reactants in subsequent reactions and avoids incomplete reactions due to uneven concentrations. Graphene oxide is ultrasonically dispersed at specific power and time with intermittent stops, which not only achieves sufficient dispersion to facilitate subsequent loading but also prevents overheating from damaging its structure. The addition of silver nitrate and sodium borohydride solutions at a specific rate while controlling the stirring speed allows silver ions to be uniformly adsorbed and reduced on the surface of graphene oxide, forming uniform silver nanoparticles and preventing agglomeration. The addition of ammonia water at a slow rate to adjust the pH to 8-9 prevents excessively high local pH from causing zinc oxide agglomeration and ensures the formation of a uniform zinc oxide shell (which can synergistically fight bacteria with silver and protect silver particles). High-speed centrifugation to separate the precipitate, washing with deionized water, and then centrifuging to pH=7 effectively removes residual impurities. Ethanol washing to remove water, vacuum drying, and pulverization and sieving ensure the purity and uniform particle size of the antibacterial agent. When the final composite antibacterial agent is applied to antibacterial polyvinyl chloride (PVC) sheets, it can achieve uniform dispersion, exerting a highly efficient and long-lasting antibacterial effect without negatively impacting the mechanical properties of the sheets.

[0021] This application also discloses a method for preparing antibacterial PVC sheets, comprising the following steps: S1. Add polyvinyl chloride resin, chlorinated polyvinyl chloride, polysulfone, polyvinylidene fluoride micro powder, multifunctional interface reinforcing agent, composite antibacterial agent, maleic anhydride-grafted ethylene-vinyl acetate copolymer, maleic anhydride-grafted polypropylene, light calcium carbonate, nano silica, calcium-zinc composite stabilizer, pentaerythritol stearate, zinc stearate, antioxidant 168, and ultraviolet absorber UV-531 to a high-speed mixer in sequence. Set the mixer speed to 1100-1300 r / min, heat to 95-105℃, and mix for 12-18 min. After mixing, turn off the heating and continue stirring until the material temperature drops to room temperature. Set aside for later use. S2. Add the mixed material to the twin-screw extruder and set the extruder temperature gradient: Zone 1: 160-170℃; Zone 2: 170-180℃; Zone 3: 180-190℃. Adjust the screw speed to 20-30 r / min and the feeding rate to 10-15 kg / h; after the material is melted, mixed and sheared by the extruder, it is extruded into strips by the die head, cooled to below 40℃ by the cooling water tank, and then pelletized by the pelletizer to obtain antibacterial polyvinyl chloride composite masterbatch; S3. Add the antibacterial PVC composite masterbatch to the calender. Set the temperature of the front roller of the calender to 185-195℃, the temperature of the rear roller to 180-190℃, and the roller speed ratio between the front and rear rollers to 1:1.4-1:1.6. Adjust the roller spacing according to the product thickness. Start the calender and put the masterbatch into the rollers. After preheating, plasticizing, and calendering, the masterbatch is formed into a continuous sheet. The sheet material is pulled to the cooling roller group by the traction machine and cooled to below 45℃. Finally, the cutting machine cuts it to the set size to obtain the finished antibacterial PVC sheet.

[0022] By setting up the above technical solutions, the high-speed mixer, operating at a speed of 1100-1300 r / min and a temperature of 95-105℃ for 12-18 minutes, ensures uniform dispersion of polyvinyl chloride resin, chlorinated polyvinyl chloride, composite antibacterial agents, and other components, avoiding local agglomeration and laying the foundation for uniform antibacterial performance and stable mechanical properties of the sheet material; the twin-screw extruder, operating at a specific temperature gradient (zone 1 160-170℃, zone 2 170-180℃, zone 3 180-190℃), can... The process ensures that the material is fully melted and does not degrade. The matched screw speed and feeding rate further guarantee the melting and mixing effect, resulting in uniform antibacterial PVC composite masterbatch. The calender uses a specific roller temperature (front roller 185-195℃, rear roller 180-190℃) and roller speed ratio to fully plasticize the masterbatch and calender it into a flat and continuous sheet. The cooling roller group cools the sheet to below 45℃ to eliminate internal stress and avoid later deformation, ultimately producing antibacterial PVC sheets with uniform antibacterial effect, stable mechanical properties, and accurate dimensions.

[0023] Preferably, during the stirring process in the heat preservation stage of step S1, a sample needs to be taken every 3 minutes to measure the material temperature with an infrared thermometer to ensure that the material temperature is uniformly controlled within the range of 95-105℃.

[0024] By implementing the above technical solution, sampling every 3 minutes and controlling the temperature with an infrared thermometer allows for more timely monitoring and adjustment of the material temperature, ensuring it remains uniformly stable within the 95-105℃ range. Under this temperature condition, it avoids both insufficient mixing and localized agglomeration of components such as PVC resin, chlorinated PVC, and composite antibacterial agents due to excessively low temperatures, and component degradation or impaired antibacterial agent activity due to excessively high temperatures. Simultaneously, the uniform temperature environment ensures the full effectiveness of interfacial compatibilizers such as maleic anhydride-grafted ethylene-vinyl acetate copolymer and lubricants such as pentaerythritol stearate, laying the foundation for the uniformity of subsequent twin-screw extrusion granulation and the stability of the final antibacterial PVC sheet's mechanical and antibacterial properties.

[0025] The beneficial effects of this invention are as follows: The matrix resin serves as the basic carrier, providing support for the molding and basic mechanical properties of the board. Heat-resistant reinforcing agents improve the board's resistance to high-temperature deformation, preventing failure at high temperatures. Fluorine-based functional agents improve the surface properties and weather resistance of the board, extending its service life outdoors or in complex environments. Multifunctional interface reinforcing agents optimize the interfacial bonding between components within the board, reducing interface defects. Composite antibacterial agents are the core component that imparts antibacterial function to antibacterial PVC boards, enabling them to have antibacterial and bacteriostatic effects. Interface compatibilizers improve the compatibility of the resin with other fillers and functional agents, ensuring uniform dispersion of all components. Fillers enhance the rigidity and dimensional stability of the board. Stabilizers inhibit the degradation of PVC resin, maintaining stable long-term performance of the board. Lubricants improve the flowability of the board during processing, preventing material adhesion to equipment and ensuring smooth molding. Antioxidants inhibit thermo-oxidative aging during processing and use, extending the board's service life. UV absorbers absorb ultraviolet rays, reducing UV damage to the board structure and further improving its weather resistance. These components work synergistically to give antibacterial PVC sheets excellent antibacterial properties while also ensuring heat resistance, compatibility, processability, aging resistance, and mechanical stability, thus meeting their application requirements.

[0026] Octadecyl-polyhedral oligomeric silsesquioxane, as the core framework material of the multifunctional interface reinforcing agent, provides an inorganic-organic hybrid polyhedral cage structure, laying the foundation for subsequent nanoscale reinforcement of antibacterial PVC sheets. 1H,1H,2H,2H-perfluorooctyl mercaptan can introduce fluorocarbon chains into the interface reinforcing agent through reaction, enabling it to form good compatibility with fluorinated functional agents in the antibacterial PVC sheets, thereby improving the interfacial bonding state of various components within the sheet. Azobisisobutyronitrile, as an initiator, can promote the full reaction between octavincyl-polyhedral oligomeric silsesquioxane and 1H,1H,2H,2H-perfluorooctyl mercaptan, ensuring the integrity of the interface reinforcing agent structure and its stable performance. Toluene, as a solvent, can uniformly dissolve and mix the above raw materials, ensuring a stable reaction. The multifunctional interface enhancer prepared from these raw materials can effectively improve the interfacial bonding force between the resin, filler, and antibacterial agent when applied to antibacterial polyvinyl chloride sheets, reduce interfacial defects, and at the same time help enhance the rigidity and heat resistance of the sheets. It can also help the antibacterial agent to be uniformly dispersed in the matrix, providing support for the synergistic optimization of the antibacterial and mechanical properties of the sheets.

[0027] Graphene oxide, as a carrier of the composite antibacterial agent, can effectively load silver nanoparticles and zinc oxide due to its high specific surface area, laying the foundation for the uniform dispersion of antibacterial components in the antibacterial PVC board and avoiding the impact of agglomeration on the antibacterial effect. Deionized water, as a solvent, can fully dissolve raw materials such as graphene oxide and silver nitrate to form a uniform dispersion, ensuring the smooth progress of each reaction step. Silver nitrate is the source of silver ions, which can destroy bacterial cell membranes and are the core component for achieving rapid antibacterial action in the board. Sodium borohydride can reduce silver ions to silver nanoparticles, enhancing the antibacterial activity of silver and further improving the antibacterial efficiency of the board. Zinc nitrate is the source of zinc and can be converted into zinc oxide. Zinc oxide can generate active oxygen under light, which works synergistically with silver ions to achieve long-lasting antibacterial action in the board. Ammonia water with a mass concentration of 25%-28% can adjust the pH value of the reaction system, helping to generate uniform zinc hydroxide and convert it into a zinc oxide shell, ensuring the structural stability of the antibacterial agent. Ethanol can be used to wash the antibacterial agent, removing residual impurities and moisture, and improving the purity of the antibacterial agent. When the composite antibacterial agent prepared from these raw materials is applied to antibacterial polyvinyl chloride (PVC) sheets, it can impart efficient, long-lasting and uniform antibacterial properties to the sheets, while its stable structure is not likely to have a negative impact on the mechanical properties of the sheets. Detailed Implementation

[0028] To make the objectives, technical solutions, and advantages of the embodiments of the present invention clearer, the technical solutions of the embodiments of the present invention will be clearly and completely described below in conjunction with the embodiments of the present invention. Obviously, the described embodiments are only some embodiments of the present invention, 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.

[0029] Example 1: This example discloses an antibacterial PVC board. By weight, the raw materials of the antibacterial PVC board include: 95 parts of SG-5 type polyvinyl chloride resin, 4 parts of chlorinated polyvinyl chloride, 2 parts of polysulfone, 1.5 parts of polyvinylidene fluoride micro powder with a particle size of 0.5-2μm, 2 parts of multifunctional interface reinforcing agent, 1.5 parts of composite antibacterial agent, 0.8 parts of maleic anhydride-grafted ethylene-vinyl acetate copolymer with a grafting rate of 1.5%, 0.5 parts of maleic anhydride-grafted polypropylene with a grafting rate of 2%, 8 parts of light calcium carbonate with a fineness of 1250 mesh, 1 part of nano-silica with a particle size of 50nm and a surface modified by silane coupling agent, 2.5 parts of calcium-zinc composite stabilizer doped with rare earth lanthanum ions, 0.8 parts of pentaerythritol stearate, 0.5 parts of zinc stearate, 0.4 parts of antioxidant 168, and 0.3 parts of ultraviolet absorber UV-531. The chlorine content of the chlorinated polyvinyl chloride is 63%, and the content of rare earth lanthanum ions in the calcium-zinc stabilizer is 2%.

[0030] The multifunctional interface reinforcing agent, by weight, comprises the following raw materials: 4 parts octavinyl-polyhedral oligomeric silsesquioxane, 8 parts 1H,1H,2H,2H-perfluorooctyl mercaptan, 0.13 parts azobisisobutyronitrile, and 95 parts toluene. The preparation method of the multifunctional interface reinforcing agent includes the following steps: 1) Select a 500mL dry three-necked flask, equip it with a stirrer, reflux condenser and nitrogen inlet tube, place the flask in a constant temperature water bath, add octavinyl-polyhedral oligomeric silsesquioxane and toluene to the three-necked flask, stir at 300r / min at room temperature for 30min until the octavinyl-polyhedral oligomeric silsesquioxane is completely dissolved and a transparent solution is formed; 2) Add 1H,1H,2H,2H-perfluorooctyl mercaptan and azobisisobutyronitrile sequentially to the transparent solution, and continue stirring at 300 r / min for 15 min to ensure uniform mixing. Then, purge the air in the flask with high-purity nitrogen gas (purity ≥99.99%) at a rate of 100 mL / min three times, each time for 10 min. After the purging is complete, maintain the nitrogen pressure at 0.01 MPa, raise the temperature of the constant temperature water bath to 70℃ at 5℃ / min, and turn on reflux (take samples every 3 h, and monitor the vinyl characteristic peak (1630 cm⁻¹) by infrared spectroscopy). -1 (Disappearance status, determine the reaction endpoint), reaction time 24 hours; 3) After the reaction is complete, turn off the heating and stirring, and cool the reaction solution to room temperature. Slowly add the cooled reaction solution dropwise to 5 times its volume of ice-cold methanol at 0°C, while stirring at 200 rpm. After a white precipitate forms, collect the precipitate by filtration using a Buchner funnel. Wash the precipitate three times repeatedly with ice-cold methanol (each time using twice the wet weight of the precipitate) until the washing solution shows no characteristic thiol peak (2570 cm⁻¹) as detected by Fourier transform infrared spectroscopy. -1 ), to remove unreacted 1H,1H,2H,2H-perfluorooctyl mercaptan and azobisisobutyronitrile; 4) The precipitate after step 3) was placed in a vacuum oven and dried for 24 hours at a temperature of 50℃ and a vacuum of -0.095MPa to obtain a multifunctional interface enhancer (fluorinated polyhedral oligomeric silsesquioxane). The fluorine content was determined to be ≥35% by elemental analysis and its crystal structure was determined by X-ray diffraction, confirming that the polyhedral cage structure was intact.

[0031] The composite antibacterial agent, by weight, comprises the following raw materials: 0.8 parts graphene oxide (purity ≥99%), 95 parts deionized water, 2 parts silver nitrate (analytical grade), 0.8 parts sodium borohydride (analytical grade), 2 parts zinc nitrate (analytical grade), 10 parts 25% ammonia solution (analytical grade), and 48 parts ethanol (analytical grade). The preparation method of the composite antibacterial agent includes the following steps: a. Dissolve silver nitrate, sodium borohydride, and zinc nitrate separately in deionized water to prepare solutions of 0.1 mol / L, 0.09 mol / L, and 0.2 mol / L, respectively; b. Add graphene oxide to deionized water and place it in an ultrasonic disperser. Set the power to 300W and the ultrasonic time to 30min. Stop the machine for 5min every 15min during the process. After the ultrasonication is completed, a graphene oxide dispersion is obtained. c. Transfer the graphene oxide dispersion to a 250 mL three-necked flask and stir at 250 r / min at room temperature. Add silver nitrate solution dropwise at a uniform rate over 15 min. After the addition is complete, continue stirring for 30 min. Then, add sodium borohydride solution dropwise at a uniform rate over 20 min. After the addition is complete, react at room temperature for 1 h to obtain a silver / graphene oxide dispersion. d. Add zinc nitrate solution to the silver / graphene oxide dispersion and stir for 10 min. Add ammonia water at a dropping rate of 1 mL / min to adjust the pH of the solution to 8. Then, place the three-necked flask in a constant temperature water bath, heat to 60℃, stir at 200 r / min for 2 h to form a zinc hydroxide coating layer. Then heat to 100℃ and keep warm for 1 h to dehydrate the zinc hydroxide and convert it into zinc oxide, thus obtaining the silver@zinc oxide / graphene oxide dispersion. e. Transfer the dispersion obtained in step d to a centrifuge tube and place it in a high-speed centrifuge. Set the speed to 8000 r / min and the centrifugation time to 10 min. Collect the precipitate and wash it three times with deionized water until the pH of the washing solution is 7. Then wash it once with ethanol to remove residual water on the surface. Finally, place the washed precipitate in a vacuum oven and set the temperature to 50℃ and the vacuum degree to -0.095 MPa. After drying for 12 h, pulverize it with a planetary ball mill and pass it through a 200-mesh sieve to obtain a composite antibacterial agent (silver@zinc oxide / graphene oxide composite antibacterial agent). Observation by transmission electron microscopy shows that the silver nanoparticles have a particle size of 15 nm, the zinc oxide shell thickness is 8 nm, and the particles on the graphene oxide sheets are uniformly dispersed. Each time the product is washed with deionized water, it needs to be centrifuged at 4900 r / min for 5 min.

[0032] This embodiment also discloses a method for preparing antibacterial PVC sheets, including the following steps: S1. Add polyvinyl chloride resin, chlorinated polyvinyl chloride, polysulfone, polyvinylidene fluoride micro powder, multifunctional interface reinforcing agent, composite antibacterial agent, maleic anhydride-grafted ethylene-vinyl acetate copolymer, maleic anhydride-grafted polypropylene, light calcium carbonate, nano silica, calcium-zinc composite stabilizer, pentaerythritol stearate, zinc stearate, antioxidant 168, and ultraviolet absorber UV-531 to a high-speed mixer in sequence. Set the mixer speed to 1100 r / min, heat to 95℃, and mix for 12 min. After mixing, turn off the heating and continue stirring until the material temperature drops to room temperature. Set aside for later use. During the stirring process in the heat preservation stage, samples need to be taken every 3 minutes to measure the material temperature with an infrared thermometer to ensure that the material temperature is uniformly controlled at 95℃. S2. Add the mixed material to the twin-screw extruder and set the extruder temperature gradient: Zone 1: 160℃; Zone 2: 170℃; Zone 3: 180℃. Adjust the screw speed to 20r / min and the feeding rate to 10kg / h; after the material is melted, mixed and sheared by the extruder, it is extruded into strips by the die head, cooled to below 40℃ by the cooling water tank, and then pelletized by the pelletizer to obtain antibacterial polyvinyl chloride composite masterbatch; S3. Add the antibacterial PVC composite masterbatch to the calender. Set the front roller temperature to 185℃, the rear roller temperature to 180℃, and the roller speed ratio between the front and rear rollers to 1:1.4. Adjust the roller spacing according to the product thickness. Start the calender and feed the masterbatch into the rollers. After preheating, plasticizing, and calendering, the masterbatch is formed into continuous sheets. The sheet material is pulled to the cooling roller group by the traction machine and cooled to below 45℃. Finally, the cutting machine cuts it to the set size to obtain the finished antibacterial PVC sheet.

[0033] Example 2: This example discloses an antibacterial PVC board. By weight, the raw materials of the antibacterial PVC board include: 105 parts of SG-5 type polyvinyl chloride resin, 9 parts of chlorinated polyvinyl chloride, 5 parts of polysulfone, 4.5 parts of polyvinylidene fluoride micro powder with a particle size of 0.5-2μm, 6 parts of multifunctional interface reinforcing agent, 5 parts of composite antibacterial agent, 2.5 parts of maleic anhydride-grafted ethylene-vinyl acetate copolymer with a grafting rate of 3%, 2 parts of maleic anhydride-grafted polypropylene with a grafting rate of 4%, 15 parts of light calcium carbonate with a fineness of 1250 mesh, 3 parts of nano-silica with a particle size of 50nm and a surface modified by silane coupling agent, 4.5 parts of calcium-zinc composite stabilizer doped with rare earth lanthanum ions, 1.8 parts of pentaerythritol stearate, 1.2 parts of zinc stearate, 0.9 parts of antioxidant 168, and 0.8 parts of ultraviolet absorber UV-531. The chlorine content of the chlorinated polyvinyl chloride is 67%, and the content of rare earth lanthanum ions in the calcium-zinc stabilizer is 5%.

[0034] The multifunctional interface reinforcing agent, by weight, comprises the following raw materials: 6 parts octavinyl-polyhedral oligomeric silsesquioxane, 12 parts 1H,1H,2H,2H-perfluorooctyl mercaptan, 0.2 parts azobisisobutyronitrile, and 105 parts toluene. The preparation method of the multifunctional interface reinforcing agent includes the following steps: 1) Select a 500mL dry three-necked flask, equip it with a stirrer, reflux condenser and nitrogen inlet tube, place the flask in a constant temperature water bath, add octavinyl-polyhedral oligomeric silsesquioxane and toluene to the three-necked flask, stir at 400r / min at room temperature for 40min until the octavinyl-polyhedral oligomeric silsesquioxane is completely dissolved and a transparent solution is formed; 2) Add 1H,1H,2H,2H-perfluorooctyl mercaptan and azobisisobutyronitrile sequentially to the transparent solution, and continue stirring at 400 r / min for 20 min to ensure uniform mixing. Then, purge the air in the flask with high-purity nitrogen gas (purity ≥99.99%) at a rate of 150 mL / min, replacing the air three times, each time for 10 min. After replacement, maintain the nitrogen pressure at 0.02 MPa, raise the temperature of the constant temperature water bath to 80℃ at 5℃ / min, and turn on reflux (take samples every 3 h, and monitor the vinyl characteristic peak (1630 cm⁻¹) by infrared spectroscopy). -1 (Disappearance status, determine the reaction endpoint), reaction time 48 hours; 3) After the reaction is complete, turn off the heating and stirring, and cool the reaction solution to room temperature. Slowly add the cooled reaction solution dropwise into 5 times the volume of ice-cold methanol at 5°C, while stirring at 300 rpm. After a white precipitate forms, collect the precipitate by filtration using a Buchner funnel. Wash the precipitate repeatedly with ice-cold methanol 5 times (each time using twice the wet weight of the precipitate) until the washing solution shows no characteristic peak of thiol (2570 cm⁻¹) as detected by Fourier transform infrared spectroscopy.-1 ), to remove unreacted 1H,1H,2H,2H-perfluorooctyl mercaptan and azobisisobutyronitrile; 4) The precipitate after step 3) was placed in a vacuum oven and dried for 24 hours at a temperature of 50℃ and a vacuum of -0.098MPa to obtain a multifunctional interface enhancer (fluorinated polyhedral oligomeric silsesquioxane). The fluorine content was determined to be ≥35% by elemental analysis and its crystal structure was determined by X-ray diffraction, confirming that the polyhedral cage structure was intact.

[0035] The composite antibacterial agent, by weight, comprises the following raw materials: 1.2 parts graphene oxide (purity ≥99%), 105 parts deionized water, 4 parts silver nitrate (analytical grade), 1.6 parts sodium borohydride (analytical grade), 4 parts zinc nitrate (analytical grade), 15 parts 28% ammonia solution (analytical grade), and 52 parts ethanol (analytical grade). The preparation method of the composite antibacterial agent includes the following steps: a. Dissolve silver nitrate, sodium borohydride, and zinc nitrate separately in deionized water to prepare solutions of 0.3 mol / L, 0.11 mol / L, and 0.5 mol / L, respectively; b. Add graphene oxide to deionized water and place it in an ultrasonic disperser. Set the power to 500W and the ultrasonic time to 60min, stopping the machine for 5min every 15min. After ultrasonication is completed, a graphene oxide dispersion is obtained. c. Transfer the graphene oxide dispersion to a 250 mL three-necked flask and stir at 300 r / min at room temperature. Add silver nitrate solution dropwise at a uniform rate over 20 min. After the addition is complete, continue stirring for 30 min. Then, add sodium borohydride solution dropwise at a uniform rate over 30 min. After the addition is complete, react at room temperature for 2 h to obtain a silver / graphene oxide dispersion. d. Add zinc nitrate solution to the silver / graphene oxide dispersion and stir for 15 min. Add ammonia water at a dropping rate of 2 mL / min to adjust the pH of the solution to 9. Then, place the three-necked flask in a constant temperature water bath, heat to 80℃, stir at 250 r / min for 4 h to form a zinc hydroxide coating layer. Then heat to 120℃ and keep warm for 2 h to dehydrate the zinc hydroxide and convert it into zinc oxide, thus obtaining the silver@zinc oxide / graphene oxide dispersion. e. Transfer the dispersion obtained in step d to a centrifuge tube and place it in a high-speed centrifuge. Set the speed to 10000 r / min and the centrifugation time to 15 min. Collect the precipitate and wash it four times with deionized water until the pH of the washing solution is 7. Then wash it once with ethanol to remove residual water on the surface. Finally, place the washed precipitate in a vacuum oven and set the temperature to 60℃ and the vacuum degree to -0.098 MPa. After drying for 24 h, pulverize it with a planetary ball mill and pass it through a 200-mesh sieve to obtain a composite antibacterial agent (silver@zinc oxide / graphene oxide composite antibacterial agent). Observation by transmission electron microscopy shows that the silver nanoparticles have a particle size of 25 nm, the zinc oxide shell thickness is 15 nm, and the particles on the graphene oxide sheets are uniformly dispersed. Each time the product is washed with deionized water, it needs to be centrifuged at 5000 r / min for 5 min.

[0036] This embodiment also discloses a method for preparing antibacterial PVC sheets, including the following steps: S1. Add polyvinyl chloride resin, chlorinated polyvinyl chloride, polysulfone, polyvinylidene fluoride micro powder, multifunctional interface reinforcing agent, composite antibacterial agent, maleic anhydride-grafted ethylene-vinyl acetate copolymer, maleic anhydride-grafted polypropylene, light calcium carbonate, nano silica, calcium-zinc composite stabilizer, pentaerythritol stearate, zinc stearate, antioxidant 168, and ultraviolet absorber UV-531 to a high-speed mixer in sequence. Set the mixer speed to 1300 r / min, heat to 105℃, and mix for 18 min. After mixing, turn off the heating and continue stirring until the material temperature drops to room temperature. Set aside for later use. During the stirring process in the heat preservation stage, samples need to be taken every 3 minutes to measure the material temperature with an infrared thermometer to ensure that the material temperature is uniformly controlled at 105℃. S2. Add the mixed material to the twin-screw extruder and set the extruder temperature gradient: Zone 1: 170℃; Zone 2: 180℃; Zone 3: 190℃. Adjust the screw speed to 30r / min and the feeding rate to 15kg / h; after the material is melted, mixed and sheared by the extruder, it is extruded into strips by the die head, cooled to below 40℃ by the cooling water tank, and then pelletized by the pelletizer to obtain antibacterial polyvinyl chloride composite masterbatch. S3. Add the antibacterial PVC composite masterbatch to the calender. Set the front roller temperature to 195℃, the rear roller temperature to 190℃, and the roller speed ratio between the front and rear rollers to 1:1.6. Adjust the roller spacing according to the product thickness. Start the calender and feed the masterbatch between the rollers. After preheating, plasticizing, and calendering, the masterbatch is formed into a continuous sheet. The sheet material is pulled to the cooling roller group by the traction machine and cooled to below 45℃. Finally, the cutting machine cuts it to the set size to obtain the finished antibacterial PVC sheet.

[0037] Example 3: This example discloses an antibacterial PVC board. By weight, the raw materials of the antibacterial PVC board include: 100 parts of SG-5 type polyvinyl chloride resin, 6 parts of chlorinated polyvinyl chloride, 3 parts of polysulfone, 3.5 parts of polyvinylidene fluoride micro powder with a particle size of 1μm, 4 parts of multifunctional interface reinforcing agent, 3 parts of composite antibacterial agent, 1.5 parts of maleic anhydride-grafted ethylene-vinyl acetate copolymer with a grafting rate of 2%, 1 part of maleic anhydride-grafted polypropylene with a grafting rate of 3%, 11 parts of light calcium carbonate with a fineness of 1250 mesh, 2 parts of nano-silica with a particle size of 50nm and a surface modified by silane coupling agent, 3.5 parts of calcium-zinc composite stabilizer doped with rare earth lanthanum ions, 1.3 parts of pentaerythritol stearate, 0.7 parts of zinc stearate, 0.7 parts of antioxidant 168, and 0.5 parts of ultraviolet absorber UV-531. The chlorine content of the chlorinated polyvinyl chloride is 65%, and the content of rare earth lanthanum ions in the calcium-zinc stabilizer is 3%.

[0038] The multifunctional interface reinforcing agent, by weight, comprises the following raw materials: 5 parts octavinyl-polyhedral oligomeric silsesquioxane, 10 parts 1H,1H,2H,2H-perfluorooctyl mercaptan, 0.16 parts azobisisobutyronitrile, and 100 parts toluene. The preparation method of the multifunctional interface reinforcing agent includes the following steps: 1) Select a 500mL dry three-necked flask, equip it with a stirrer, reflux condenser and nitrogen inlet tube, place the flask in a constant temperature water bath, add octavinyl-polyhedral oligomeric silsesquioxane and toluene to the three-necked flask, stir at 350r / min at room temperature for 35min until the octavinyl-polyhedral oligomeric silsesquioxane is completely dissolved and a transparent solution is formed; 2) Add 1H,1H,2H,2H-perfluorooctyl mercaptan and azobisisobutyronitrile sequentially to the transparent solution, and continue stirring at 350 r / min for 17 min to ensure uniform mixing. Then, purge the air in the flask with high-purity nitrogen gas (purity ≥99.99%) at a rate of 125 mL / min, replacing the air three times, each time for 10 min. After replacement, maintain the nitrogen pressure at 0.015 MPa, raise the temperature of the constant temperature water bath to 75℃ at 5℃ / min, and turn on reflux (take samples every 3 h, and monitor the vinyl characteristic peak (1630 cm⁻¹) by infrared spectroscopy). -1 (The disappearance status is used to determine the reaction endpoint), and the reaction time is 36 hours. 3) After the reaction is complete, turn off the heating and stirring, and cool the reaction solution to room temperature. Slowly add the cooled reaction solution dropwise into 5 times the volume of ice-cold methanol at 2°C, while stirring at 250 rpm. After a white precipitate forms, collect the precipitate by filtration using a Buchner funnel. Wash the precipitate repeatedly with ice-cold methanol 4 times (each time using twice the wet weight of the precipitate) until the washing solution shows no characteristic peak of thiol (2570 cm⁻¹) as detected by Fourier transform infrared spectroscopy.-1 ), to remove unreacted 1H,1H,2H,2H-perfluorooctyl mercaptan and azobisisobutyronitrile; 4) The precipitate after step 3) was placed in a vacuum oven and dried for 24 hours at a temperature of 50℃ and a vacuum of -0.096MPa to obtain a multifunctional interface enhancer (fluorinated polyhedral oligomeric silsesquioxane). The fluorine content was determined to be ≥35% by elemental analysis and its crystal structure was determined by X-ray diffraction, confirming that the polyhedral cage structure was intact.

[0039] The composite antibacterial agent, by weight, comprises the following raw materials: 1 part graphene oxide (purity ≥99%), 100 parts deionized water, 3 parts silver nitrate (analytical grade), 1.2 parts sodium borohydride (analytical grade), 3 parts zinc nitrate (analytical grade), 12 parts 26% ammonia solution (analytical grade), and 50 parts ethanol (analytical grade). The preparation method of the composite antibacterial agent includes the following steps: a. Dissolve silver nitrate, sodium borohydride, and zinc nitrate separately in deionized water to prepare solutions of 0.2 mol / L, 0.1 mol / L, and 0.3 mol / L respectively; b. Add graphene oxide to deionized water and place it in an ultrasonic disperser. Set the power to 400W and the ultrasonic time to 45min. Stop the machine for 5min every 15min during the process. After the ultrasonication is completed, a graphene oxide dispersion is obtained. c. Transfer the graphene oxide dispersion to a 250 mL three-necked flask and stir at 275 r / min at room temperature. Add silver nitrate solution dropwise at a uniform rate over 17 min. After the addition is complete, continue stirring for 30 min. Then, add sodium borohydride solution dropwise at a uniform rate over 25 min. After the addition is complete, react at room temperature for 1.5 h to obtain a silver / graphene oxide dispersion. d. Add zinc nitrate solution to the silver / graphene oxide dispersion and stir for 12 min. Add ammonia water at a dropping rate of 1.5 mL / min to adjust the pH of the solution to 8.5. Then, place the three-necked flask in a constant temperature water bath, heat to 70℃, stir at 225 r / min for 3 h to form a zinc hydroxide coating layer. Then heat to 110℃ and keep warm for 1.5 h to dehydrate the zinc hydroxide and convert it into zinc oxide, thus obtaining the silver@zinc oxide / graphene oxide dispersion. e. Transfer the dispersion obtained in step d to a centrifuge tube and place it in a high-speed centrifuge. Set the speed to 9000 r / min and the centrifugation time to 12 min. Collect the precipitate and wash it three times with deionized water until the pH of the washing solution is 7. Then wash it once with ethanol to remove residual water on the surface. Finally, place the washed precipitate in a vacuum oven and set the temperature to 55℃ and the vacuum degree to -0.096 MPa. After drying for 18 h, pulverize it with a planetary ball mill and pass it through a 200-mesh sieve to obtain a composite antibacterial agent (silver@zinc oxide / graphene oxide composite antibacterial agent). Observation by transmission electron microscopy shows that the silver nanoparticles have a particle size of 20 nm, the zinc oxide shell thickness is 11 nm, and the particles on the graphene oxide sheets are uniformly dispersed. Each time the product is washed with deionized water, it needs to be centrifuged at 4950 r / min for 5 min.

[0040] This embodiment also discloses a method for preparing antibacterial PVC sheets, including the following steps: S1. Add polyvinyl chloride resin, chlorinated polyvinyl chloride, polysulfone, polyvinylidene fluoride micro powder, multifunctional interface reinforcing agent, composite antibacterial agent, maleic anhydride-grafted ethylene-vinyl acetate copolymer, maleic anhydride-grafted polypropylene, light calcium carbonate, nano silica, calcium-zinc composite stabilizer, pentaerythritol stearate, zinc stearate, antioxidant 168, and ultraviolet absorber UV-531 to a high-speed mixer in sequence. Set the mixer speed to 1200 r / min, heat to 100℃, and mix for 15 min. After mixing, turn off the heating and continue stirring until the material temperature drops to room temperature. Set aside for later use. During the stirring process in the heat preservation stage, samples need to be taken every 3 minutes to measure the material temperature with an infrared thermometer to ensure that the material temperature is uniformly controlled at 100℃. S2. Add the mixed material to the twin-screw extruder and set the extruder temperature gradient: Zone 1: 165℃; Zone 2: 175℃; Zone 3: 185℃. Adjust the screw speed to 25r / min and the feeding rate to 12kg / h; after the material is melted, mixed and sheared by the extruder, it is extruded into strips by the die head, cooled to below 40℃ by the cooling water tank, and then pelletized by the pelletizer to obtain antibacterial polyvinyl chloride composite masterbatch; S3. Add the antibacterial PVC composite masterbatch to the calender. Set the front roller temperature to 190℃, the rear roller temperature to 185℃, and the roller speed ratio between the front and rear rollers to 1:1.5. Adjust the roller spacing according to the product thickness. Start the calender and feed the masterbatch between the rollers. After preheating, plasticizing, and calendering, the masterbatch is formed into a continuous sheet. The sheet material is pulled to the cooling roller group by the traction machine and cooled to below 45℃. Finally, the cutting machine cuts it to the set size to obtain the finished antibacterial PVC sheet.

[0041] Comparative Example 1: An antibacterial PVC board and its preparation method are disclosed. The only difference between this PVC board and Example 3 is that no fluorinated polyhedral oligomeric silsesquioxane is added, while the other components and process parameters are the same as in Example 3.

[0042] Comparative Example 2: An antibacterial PVC board and its preparation method are disclosed. The only difference between this PVC board and Example 3 is that the silver@zinc oxide / graphene oxide composite antibacterial agent is not added, while the other components and process parameters are the same as in Example 3.

[0043] Comparative Example 3: An antibacterial PVC board and its preparation method are disclosed. The only difference between this PVC board and Example 3 is that ordinary polyhedral oligomeric silsesquioxane (fluorine-free modified) is used instead of fluorinated polyhedral oligomeric silsesquioxane. Other components and process parameters are the same as in Example 3.

[0044] Comparative Example 4: An antibacterial PVC board and its preparation method are disclosed. The only difference between this PVC board and Example 3 is that pure silver nitrate is used instead of silver@zinc oxide / graphene oxide composite antibacterial agent, while other components and process parameters are the same as in Example 3.

[0045] Comparative Example 5: An antibacterial PVC board and its preparation method are disclosed. The only difference between this PVC board and Example 3 is that maleic anhydride-grafted polypropylene is not added (only maleic anhydride-grafted ethylene-vinyl acetate copolymer is retained), while other components and process parameters are the same as in Example 3.

[0046] Comparative Example 6: An antibacterial PVC sheet and its preparation method are disclosed. The only difference between this PVC sheet and Example 3 is that the temperature of Zone 1 (feeding section) of the twin-screw extruder is reduced to 140-150℃, while the other components and process parameters are the same as in Example 3.

[0047] Comparative Example 7: An antibacterial PVC board and its preparation method are disclosed. The only difference between this PVC board and Example 3 is that polysulfone is not added (only chlorinated polyvinyl chloride is retained), while other components and process parameters are the same as in Example 3.

[0048] Comparative Example 8: An antibacterial PVC board and its preparation method are disclosed. The only difference between this PVC board and Example 3 is that ordinary calcium carbonate (300 mesh) is used instead of light calcium carbonate (1250 mesh) and nano silica. Other components and process parameters are the same as in Example 3.

[0049] Comparative Example 9: An antibacterial PVC board and its preparation method are disclosed. The only difference between this PVC board and Example 3 is that the calcium-zinc composite stabilizer (doped with rare earth lanthanum ions) is replaced with a common calcium-zinc stabilizer (without rare earth lanthanum ion doping). Other components and process parameters are the same as in Example 3.

[0050] Comparative Example 10: An antibacterial PVC board and its preparation method are disclosed. The only difference between this PVC board and Example 3 is that the ultraviolet absorber UV-531 is not added, while the other components and process parameters are the same as in Example 3.

[0051] Comparative Example 11: An antibacterial PVC board and its preparation method are disclosed. The only difference between this PVC board and Example 3 is that fluorinated polyhedral oligomeric silsesquioxane and silver@zinc oxide / graphene oxide composite antibacterial agent are not added. Other components and process parameters are the same as in Example 3.

[0052] The PVC sheets obtained in Examples 1-3 and Comparative Examples 1-11 were subjected to performance tests for antibacterial rate, antibacterial rate after aging, tensile strength, impact strength, Vicat softening point, and silver ion precipitation. The test methods and standards for each performance are as follows: (i) Antibacterial rate test (performed in accordance with GB / T 31402-2015 "Test method for antibacterial properties of plastic surfaces") (1) Sample preparation: Cut three 100mm×100mm×(1.2-2.2mm) samples from the antibacterial polyvinyl chloride sheet, wipe the sample surface with 75% ethanol solution, and place them on a sterile operating table to air dry (air drying time 30min).

[0053] (2) Preparation of bacterial suspension: Escherichia coli and Staphylococcus aureus were inoculated into nutrient broth medium and cultured in a constant temperature incubator at 37℃ for 18-24 h to obtain bacterial suspension; the bacterial suspension was diluted with sterile physiological saline to a concentration of 1×10⁻⁶. 5 -5×10 5 CFU / mL was used as the test bacterial solution.

[0054] (3) Inoculation and culture: Under aseptic conditions, take 0.4 mL of test bacterial solution and drop it evenly onto the surface of the sample. Cover it with a sterile polyethylene film (40 mm × 40 mm) (to ensure that the bacterial solution is in full contact with the sample surface and there are no air bubbles). Place the sample in a sterile culture dish and culture it in a constant temperature and humidity incubator at 37°C and a relative humidity of more than 90% for 24 h.

[0055] (4) Colony counting: After the culture is completed, remove the polyethylene film with sterile forceps, place the sample into an Erlenmeyer flask containing 10 mL of sterile physiological saline, and shake on a shaker (150 r / min) for 10 min to fully elute the bacteria on the sample surface and obtain the eluent; take 1 mL of the eluent and serially dilute it with sterile physiological saline (10 mL / min). 0 10 1 10 2 Take 0.1 mL of each dilution of eluent and add it dropwise onto a nutrient agar plate. Spread the plate evenly with a sterile spreader. Incubate the plate at 37°C for 24 hours. Count the number of colonies on the plate and calculate the number of colonies per milliliter of eluent (CFU / mL).

[0056] (5) Antibacterial rate calculation: At the same time, use the PVC board (same size) without antibacterial agent as blank sample, and follow the above steps to calculate the number of colonies in the blank sample; Antibacterial rate (%) = (number of colonies in blank sample - number of colonies in test sample) / number of colonies in blank sample × 100. Take the average value of the 3 samples as the final antibacterial rate.

[0057] (ii) Antibacterial rate test after aging (conducted in accordance with GB / T 16422.2-2014 "Laboratory Light Source Exposure Test Methods for Plastics - Part 2: Xenon Arc Lamp" and GB / T 31402-2015) (1) Aging treatment: Three samples of 100mm×100mm×(1.2-2.2mm) were cut from the antibacterial polyvinyl chloride sheet and placed in a xenon arc lamp aging test chamber; the aging conditions were set as follows: temperature 50℃, relative humidity 65%, and irradiance 0.71W / (m²). 2 •420nm), aging time 168h; during the aging process, check the sample surface every 24h for cracks, discoloration and other phenomena.

[0058] (2) Antibacterial rate test: After aging, the sample is taken out and the antibacterial rate of the aged sample is tested according to step 2-5 of “(I) Antibacterial rate test”. The average value of the three samples is taken as the final antibacterial rate after aging.

[0059] (iii) Tensile strength test (performed in accordance with GB / T 1040.3-2006 "Determination of tensile properties of plastics - Part 3: Test conditions for films and sheets") (1) Sample preparation: Cut five Type I samples (150 mm in length, 10 mm in width, 1.2-2.2 mm in thickness, and 50 mm in gauge length) from the antibacterial polyvinyl chloride sheet. Measure the width and thickness of the gauge length of the sample with calipers (accurate to 0.01 mm) and take the average value of the three measurement points as the sample size.

[0060] (2) Test conditions: Adjust the ambient temperature of the universal testing machine (model CMT6104) to 23℃ and the relative humidity to 50%; set the tensile speed to 50mm / min and the extensometer gauge length to 50mm, and connect the extensometer to the gauge length section of the specimen.

[0061] (3) Test process: Clamp both ends of the specimen in the upper and lower clamps of the testing machine respectively, ensuring that the specimen axis is consistent with the direction of the tensile force and there is no skew; start the testing machine, start the tensile test, and record the tensile force and displacement data in real time until the specimen breaks; record the maximum tensile force (N) when the specimen breaks.

[0062] (4) Tensile strength calculation: Tensile strength (MPa) = maximum tensile force (N) / (specimen width (mm) × specimen thickness (mm)) Take the average value of 5 specimens as the final tensile strength.

[0063] (iv) Impact strength test (performed in accordance with GB / T 1043.1-2008 "Determination of impact properties of simply supported plastic beams - Part 1: Non-instrumental impact test") (1) Sample preparation: Cut five Type A unnotched samples (80mm in length, 10mm in width, and 1.2-2.2mm in thickness) from the antibacterial polyvinyl chloride sheet. Grind both ends of the sample with sandpaper to ensure that the sample surface is flat and free of burrs.

[0064] (2) Test conditions: Adjust the test environment temperature of the simply supported beam impact testing machine (model XJUD-5.5) to 23℃; select the appropriate pendulum energy (2.75J pendulum is selected in this scheme) according to the estimated impact strength of the sample, adjust the pendulum to the starting position, and calibrate the zero point of the testing machine.

[0065] (3) Test process: Place the sample on the support of the testing machine, ensuring that the length direction of the sample is perpendicular to the axis of the support and the midpoint of the sample is aligned with the impact edge of the pendulum; release the pendulum, impact the sample, and record the remaining energy after the impact of the pendulum; if the sample does not break, replace it with a pendulum with a larger energy and test again.

[0066] (4) Impact strength calculation: Impact strength (kJ / m 2 = (Initial energy of pendulum - Remaining energy of pendulum) / (Specimen width (mm) × Specimen thickness (mm)) × 1000. Take the average value of 5 specimens as the final impact strength.

[0067] (v) Vicat softening point test (performed in accordance with GB / T 1633-2000 "Determination of Vicat softening temperature (VST) of thermoplastics") Sample preparation: Cut three 10mm×10mm×(1.2-2.2mm) samples from the antibacterial PVC sheet, and polish the sample surface with sandpaper to ensure that the sample thickness is uniform and free of air bubbles.

[0068] (1) Test conditions: The temperature of the heating medium (silicone oil) of the Vicat softening point tester (model XRW-300A) was adjusted to 23℃; the load was set to 50N, the needle diameter was 1.13mm, and the heating rate was 50℃ / h.

[0069] (2) Test process: Place the sample in the heating medium and make the upper surface of the sample flush with the liquid surface of the heating medium; press the needle tip on the center of the upper surface of the sample and apply a 50N load; start the heating device and heat up at a rate of 50℃ / h, and record the temperature when the needle tip penetrates the sample to a depth of 1mm in real time.

[0070] (3) Results record: The average test temperature of the three samples was taken as the final Vicat softening point.

[0071] (vi) Detection of silver ion precipitation (in accordance with GB / T 23443-2009 Antibacterial Plastic Parts for Toilets) (1) Sample preparation: Cut three samples of 50mm×50mm×(1.2-2.2mm) from the antibacterial polyvinyl chloride sheet, clean the sample surface with deionized water, dry in an oven at 60℃ for 2h, and weigh after cooling to room temperature (accurate to 0.001g).

[0072] (2) Soaking treatment: Place the sample in a 500mL polytetrafluoroethylene beaker, add deionized water (bath ratio 1:50, i.e., sample mass (g): deionized water volume (mL) = 1:50); place the beaker in a 40℃ constant temperature water bath, seal the mouth of the beaker, and soak for 24h.

[0073] (3) Detection process: After soaking, 10 mL of soaking solution was taken with a pipette and filtered through a 0.22 μm organic filter membrane to remove impurities; the concentration of silver ions in the filtered soaking solution was detected by an inductively coupled plasma mass spectrometer (model NexION 350D) (detection conditions: radio frequency power 1550W, nebulizer flow rate 1.05 L / min, integration time 0.1 s); at the same time, a blank test was performed (only deionized water was soaked under the same conditions for 24 h) and the blank value was subtracted.

[0074] (4) Calculation of silver ion deposition amount: Silver ion deposition amount (μg / cm³) 2 = (Silver ion concentration in immersion solution (μg / L) × Volume of immersion solution (L)) / Surface area of ​​sample (cm²) 2 ) Sample surface area = 2 × (sample length (cm) × sample width (cm) + sample length (cm) × sample thickness (cm) + sample width (cm) × sample thickness (cm)) Take the average value of 3 samples as the final silver ion precipitation amount.

[0075] The results are shown in Table 1.

[0076] Table 1 Performance parameters of PVC sheets obtained in Examples 1-3 and Comparative Examples 1-11

[0077] Referring to Table 1, and taking Example 3 as a reference: Comparative Example 1 (without added fluorinated polyhedral oligomeric silsesquioxane): Antibacterial properties: The antibacterial rate against *Escherichia coli* decreased by 7.4% (from 99.9% to 92.5%), and the antibacterial rate against *Staphylococcus aureus* decreased by 8.0% (from 99.8% to 91.8%). After aging, the antibacterial rate against *Escherichia coli* decreased by 13.5% (from 99.7% to 86.2%), and the antibacterial rate against *Staphylococcus aureus* decreased by 14.2% (from 99.6% to 85.5%). This is because the absence of fluorinated polyhedral oligomeric silsesquioxane prevents the formation of a "fluorinated network structure," leading to severe aggregation of the silver@zinc oxide / graphene oxide composite antibacterial agent, reducing antibacterial contact sites, and making the antibacterial agent prone to detachment from the matrix during aging.

[0078] Mechanical properties: Tensile strength decreased by 31.5% (from 54 MPa to 37 MPa), and impact strength decreased by 39.6% (from 13.9 kJ / m²). 2 Reduced to 8.4 kJ / m 2 The reason is that the lack of nano-reinforcing effect of fluorinated polyhedral oligomeric silsesquioxane and the "fluorine network-graphene oxide" supporting framework leads to an increase in interface defects inside the matrix and a decrease in stress transfer efficiency.

[0079] Heat resistance: The Vicat softening point decreased by 23.5% (from 115℃ to 88℃). This is because the "rigid-heat-resistant synergistic network" of fluorinated polyhedral oligomeric silsesquioxane with chlorinated polyvinyl chloride and polysulfone failed, resulting in increased molecular chain creep and a decrease in heat distortion temperature.

[0080] Safety: Silver ion precipitation increased 34-fold (from 0.004 μg / cm³). 2 Increased to 0.14 μg / cm 2 The reason is that the non-fluorinated polyhedral oligomeric silsesquioxane anchors and fixes the antibacterial agent, making it easy for silver ions to precipitate from matrix defects.

[0081] Comparative Example 2 (without silver@zinc oxide / graphene oxide composite antibacterial agent): Antibacterial properties: The antibacterial activity against Escherichia coli and Staphylococcus aureus is almost completely lost (decreased from 99.9% and 99.8% to 0.8% and 0.5%, respectively), and the antibacterial rate further decreases to 0.6% and 0.3% after aging. The reason is that the silver@zinc oxide / graphene oxide composite antibacterial agent is the core of the antibacterial function of the board. Without it, no silver ions and hydroxyl radicals are generated, and the bacterial structure cannot be destroyed.

[0082] Mechanical properties: Tensile strength decreased by 18.5% (from 54 MPa to 44 MPa), and impact strength decreased by 28.0% (from 13.9 kJ / m²). 2 Reduced to 10.0 kJ / m 2 The reason is that the two-dimensional sheet-like reinforcement of graphene oxide is missing, which reduces the rigidity and toughness of the matrix.

[0083] Heat resistance: The Vicat softening point decreased by 11.3% (from 115℃ to 102℃). This is because the inhibitory effect of graphene oxide on molecular chain creep disappears, resulting in a decrease in heat distortion temperature.

[0084] Safety: Silver ion precipitation increased by 186.5 times (from 0.004 μg / cm³). 2 Increased to 0.75 μg / cm 2 The reason is that without the addition of a compound antibacterial agent, trace amounts of free silver ions (from raw material impurities) in the matrix are not coated and fixed, resulting in a large amount of precipitation.

[0085] Comparative Example 3 (Using ordinary polyhedral oligomeric silsesquioxane instead of fluorinated polyhedral oligomeric silsesquioxane): Antibacterial properties: The antibacterial rate against Escherichia coli decreased by 4.8% (from 99.9% to 95.1%), and the antibacterial rate against Staphylococcus aureus decreased by 5.3% (from 99.8% to 94.5%). After aging, the antibacterial rate against Escherichia coli decreased by 9.4% (from 99.7% to 90.3%), and the antibacterial rate against Staphylococcus aureus decreased by 10.0% (from 99.6% to 89.6%). This is because ordinary polyhedral oligomeric silsesquioxanes lack fluorine groups, resulting in poor compatibility with polyvinylidene fluoride (PVDF) and an inability to form a stable "fluorine-based network," leading to decreased uniformity of antibacterial agent dispersion.

[0086] Mechanical properties: Tensile strength decreased by 24.1% (from 54 MPa to 41 MPa), and impact strength decreased by 33.8% (from 13.9 kJ / m²). 2 Reduced to 9.2 kJ / m 2 The reason is the absence of the fluorine network, which weakens the interfacial bonding force and hinders stress transmission.

[0087] Heat resistance: The Vicat softening point decreased by 17.4% (from 115℃ to 95℃). This is because the synergistic heat resistance effect of the fluorine groups with chlorinated polyvinyl chloride and polysulfone disappears, and the heat resistance stability of the molecular chain decreases.

[0088] Safety: Silver ion precipitation increased 19-fold (from 0.004 μg / cm³). 2 Increased to 0.08 μg / cm 2 The reason is that the anchoring effect of the fluorine-free group makes the antibacterial agent prone to micro-migration, increasing the amount of silver ions released.

[0089] Comparative Example 4 (pure silver nitrate replacing silver @ zinc oxide / graphene oxide composite antibacterial agent): Antibacterial properties: The antibacterial rate against *Escherichia coli* decreased by 10.1% (from 99.9% to 89.8%), and the antibacterial rate against *Staphylococcus aureus* decreased by 10.8% (from 99.8% to 89.0%). After aging, the antibacterial rate against *Escherichia coli* decreased by 22.2% (from 99.7% to 77.5%), and the antibacterial rate against *Staphylococcus aureus* decreased by 22.8% (from 99.6% to 76.8%). This is because the silver ions in pure silver nitrate lack the protection of a zinc oxide shell and graphene oxide carrier, making them easily oxidized to silver oxide (Ag₂O) and inactivated. Furthermore, there is no synergistic antibacterial effect from hydroxyl radicals, resulting in a narrower antibacterial spectrum (only weak antibacterial activity against Gram-negative bacteria).

[0090] Mechanical properties: Tensile strength decreased by 25.9% (from 54 MPa to 40 MPa), and impact strength decreased by 31.7% (from 13.9 kJ / m²). 2 Reduced to 9.5 kJ / m 2 The reason is that the reinforcing effect of the lack of graphene oxide is reduced, resulting in decreased mechanical properties of the matrix.

[0091] Heat resistance: The Vicat softening point decreased by 21.7% (from 115℃ to 90℃). This is because the supporting effect of graphene oxide on the molecular chains disappears, resulting in a decrease in the heat distortion temperature.

[0092] Safety: Silver ion precipitation increased 274-fold (from 0.004 μg / cm³). 2 Increased to 1.1 μg / cm 2 (), far exceeding the 0.1 μg / cm specified in GB / T23443-2009. 2 Limit. The reason is that silver ions in pure silver nitrate have no coating structure and are easily and rapidly released to the outside of the matrix.

[0093] Comparative Example 5 (Polypropylene grafted without maleic anhydride): Antibacterial properties: The antibacterial rate against *Escherichia coli* decreased by 3.6% (from 99.9% to 96.3%), and the antibacterial rate against *Staphylococcus aureus* decreased by 4.0% (from 99.8% to 95.8%). After aging, the antibacterial rate against *Escherichia coli* decreased by 7.9% (from 99.7% to 91.8%), and the antibacterial rate against *Staphylococcus aureus* decreased by 8.4% (from 99.6% to 91.2%). This is because the maleic anhydride-grafted polypropylene lacks synergistic compatibilization with the maleic anhydride-grafted ethylene-vinyl acetate copolymer, resulting in uneven dispersion of the filler and antibacterial agent and the formation of localized antibacterial blind spots.

[0094] Mechanical properties: Tensile strength decreased by 22.2% (from 54 MPa to 42 MPa). This is because the interfacial "bridging structure" is incomplete, the bonding force between the filler and the resin interface decreases, and stress cannot be effectively transferred.

[0095] Heat resistance: The Vicat softening point decreased by 10.4% (from 115℃ to 103℃). This is because the number of interfacial defects increases, and molecular chains are more prone to slippage at high temperatures, resulting in a lower heat distortion temperature.

[0096] Safety: Silver ion precipitation increased 44-fold (from 0.004 μg / cm³). 2 Increased to 0.18 μg / cm 2 The reason is that silver ion migration channels are easily formed at interface defects, leading to an increase in the amount of silver ion precipitation.

[0097] Comparative Example 6 (Extruder Zone 1 temperature reduced to 140-150℃): Antibacterial properties: The antibacterial rate against Escherichia coli decreased by 2.1% (from 99.9% to 97.8%), and the antibacterial rate against Staphylococcus aureus decreased by 2.3% (from 99.8% to 97.5%). After aging, the antibacterial rate against Escherichia coli decreased by 6.2% (from 99.7% to 93.5%), and the antibacterial rate against Staphylococcus aureus decreased by 6.6% (from 99.6% to 93.0%). This was because the temperature in zone one of the extruder was too low, resulting in insufficient cross-linking reaction between the fluorinated polyhedral oligomeric silsesquioxane and polyvinyl chloride and polyvinylidene fluoride, leading to decreased uniformity of antibacterial agent dispersion.

[0098] Mechanical properties: Tensile strength decreased by 16.7% (from 54 MPa to 45 MPa), and impact strength decreased by 21.6% (from 13.9 kJ / m²). 2 Reduced to 10.9 kJ / m 2 The reason is insufficient cross-linking, which weakens the entanglement of matrix molecular chains and reduces mechanical properties.

[0099] Heat resistance: The Vicat softening point decreased by 6.1% (from 115℃ to 108℃). This is because the cross-linked network is incomplete, and the molecular chains are prone to creep at high temperatures, resulting in a lower heat distortion temperature.

[0100] Safety: Silver ion precipitation increased 17.5 times (from 0.004 μg / cm³). 2 Increased to 0.07 μg / cm 2 The reason is that insufficient cross-linking leads to a loose matrix structure, making it easy for silver ions to precipitate out from the intermolecular gaps.

[0101] Comparative Example 7 (without polysulfone): Antibacterial properties: The antibacterial rate against Escherichia coli decreased by 8.7% (from 99.9% to 91.2%), and the antibacterial rate against Staphylococcus aureus decreased by 9.3% (from 99.8% to 90.5%). After aging, the antibacterial rate against Escherichia coli decreased by 16.7% (from 99.7% to 83.1%), and the antibacterial rate against Staphylococcus aureus decreased by 17.3% (from 99.6% to 82.4%). This is because the addition of polysulfone resulted in an incomplete "rigid-heat-resistant synergistic network" between chlorinated polyvinyl chloride and fluorinated polyhedral oligomeric silsesquioxane, making the matrix prone to deformation and causing the antibacterial agent to detach during high-temperature aging.

[0102] Mechanical properties: Tensile strength decreased by 35.2% (from 54 MPa to 35 MPa), and impact strength decreased by 44.0% (from 13.9 kJ / m²). 2 Reduced to 7.8 kJ / m 2 The reason is that the rigid aromatic ring skeleton of polysulfone is missing, which significantly reduces the overall rigidity and toughness of the matrix.

[0103] Heat resistance: The Vicat softening point decreased by 20.0% (from 115℃ to 92℃). This is because the supporting effect of polysulfone on the molecular chain disappears, resulting in a significant reduction in the heat distortion temperature.

[0104] Safety: Silver ion precipitation increased by 212.5 times (from 0.004 μg / cm³). 2 Increased to 0.85 μg / cm 2 The reason is that the heat resistance of the matrix decreases, the molecular chain peristalsis intensifies at high temperatures, and silver ions are easily precipitated from the matrix.

[0105] Comparative Example 8 (Ordinary calcium carbonate replacing light calcium carbonate and nano-silica): Antibacterial properties: The antibacterial rate against Escherichia coli decreased by 4.3% (from 99.9% to 95.6%), and the antibacterial rate against Staphylococcus aureus decreased by 4.7% (from 99.8% to 95.1%). After aging, the antibacterial rate against Escherichia coli decreased by 8.6% (from 99.7% to 91.1%), and the antibacterial rate against Staphylococcus aureus decreased by 9.1% (from 99.6% to 90.5%). This is because ordinary calcium carbonate (300 mesh) has a large particle size (approximately 45 μm), a small specific surface area, poor interfacial bonding with resin, and lacks the dimensional stabilizing effect of nano-silica. Furthermore, the matrix is ​​prone to shrinkage during aging, resulting in uneven distribution of the antibacterial agent.

[0106] Mechanical properties: Tensile strength decreased by 25.9% (from 54 MPa to 40 MPa), and impact strength decreased by 34.5% (from 13.9 kJ / m²). 2 Reduced to 9.1 kJ / m 2 The reason is that ordinary calcium carbonate is unevenly dispersed, forming stress concentration points, which easily triggers crack propagation.

[0107] Heat resistance: The Vicat softening point decreased by 13.0% (from 115℃ to 100℃). This is because the absence of nano-silica eliminates its inhibitory effect on molecular chain peristalsis, resulting in a decrease in heat distortion temperature.

[0108] Safety: Silver ion precipitation increased 21.5 times (from 0.004 μg / cm³). 2 Increased to 0.09 μg / cm 2 The reason is that there are more defects at the interface between ordinary calcium carbonate and resin, and silver ions are more likely to precipitate from the defects.

[0109] Comparative Example 9 (Using common calcium-zinc stabilizer instead of rare earth-doped calcium-zinc stabilizer): Antibacterial properties: The antibacterial rate against *Escherichia coli* decreased by 5.6% (from 99.9% to 94.3%), and the antibacterial rate against *Staphylococcus aureus* decreased by 6.0% (from 99.8% to 93.8%). After aging, the antibacterial rate against *Escherichia coli* decreased by 11.0% (from 99.7% to 88.7%), and the antibacterial rate against *Staphylococcus aureus* decreased by 11.7% (from 99.6% to 88.0%). This is because ordinary calcium-zinc stabilizers lack rare earth lanthanum ions, making it impossible to form coordination bonds with silver ions. Silver ions are easily oxidized to silver oxide and deactivated. Furthermore, the absence of lanthanum ions promotes the photocatalytic activity of zinc oxide, resulting in a reduction in the generation of hydroxyl radicals.

[0110] Mechanical properties: Tensile strength decreased by 20.4% (from 54 MPa to 43 MPa), and impact strength decreased by 26.6% (from 13.9 kJ / m²). 2 Reduced to 10.2 kJ / m 2The reason is that the stabilizing effect of rare earth lanthanum ions on the resin molecular chain disappears, and thermo-oxidative aging leads to chain breakage, resulting in reduced mechanical properties.

[0111] Heat resistance: The Vicat softening point decreased by 12.2% (from 115℃ to 101℃). This is because the reinforcing effect of lanthanum ions on the molecular chain polarity disappears, resulting in a decrease in the heat distortion temperature.

[0112] Safety: Silver ion precipitation increased 54-fold (from 0.004 μg / cm³). 2 Increased to 0.22 μg / cm 2 The reason is that without the coordination fixation of lanthanum ions, silver ions are easily precipitated from the matrix.

[0113] Comparative Example 10 (without UV absorber UV-531): Antibacterial properties: The antibacterial rate against Escherichia coli decreased by 6.4% (from 99.9% to 93.5%), and the antibacterial rate against Staphylococcus aureus decreased by 6.8% (from 99.8% to 93.0%). After aging, the antibacterial rate against Escherichia coli decreased by 14.5% (from 99.7% to 85.2%), and the antibacterial rate against Staphylococcus aureus decreased by 15.2% (from 99.6% to 84.5%). This is because the UV absorber UV-531 was not added. UV light directly damaged the silver@zinc oxide structure (zinc oxide underwent photocorrosion, generating zinc hydroxide), causing silver ions to oxidize and become inactive. Furthermore, UV light caused the PVC molecular chains to break, leading to the detachment of the antibacterial agent.

[0114] Mechanical properties: Tensile strength decreased by 18.5% (from 54 MPa to 44 MPa), and impact strength decreased by 27.3% (from 13.9 kJ / m²). 2 Reduced to 10.1 kJ / m 2 The reason is that ultraviolet aging causes the resin molecular chains to break down, reducing the toughness of the matrix.

[0115] Heat resistance: The Vicat softening point decreased by 9.6% (from 115℃ to 104℃). This is because the thermal stability decreases and the heat distortion temperature drops after the molecular chains break.

[0116] Safety: Silver ion precipitation increased 36.5 times (from 0.004 μg / cm³). 2 Increased to 0.15 μg / cm 2 The reason is that ultraviolet light causes microcracks in the matrix, and silver ions are released from the cracks.

[0117] Comparative Example 11 (blank control, without added fluorinated polyhedral oligomeric silsesquioxane and silver@zinc oxide / graphene oxide): Antibacterial properties: The antibacterial rate against both Escherichia coli and Staphylococcus aureus is 0, and remains 0 even after aging. This is because it contains no antibacterial components and therefore cannot produce an antibacterial effect.

[0118] Mechanical properties: Tensile strength decreased by 42.6% (from 54 MPa to 31 MPa), and impact strength decreased by 51.8% (from 13.9 kJ / m²). 2 Reduced to 6.7 kJ / m 2 The reason is the lack of reinforcement from fluorinated polyhedral oligomeric silsesquioxanes and graphene oxide, which significantly reduces the mechanical properties of the matrix.

[0119] Heat resistance: The Vicat softening point decreased by 37.4% (from 115℃ to 72℃), approaching the performance of pure PVC sheets. This is because the "rigid-heat resistant synergistic network" completely failed, resulting in poor thermal stability.

[0120] Safety: Silver ion precipitation increased 574 times (from 0.004 μg / cm³). 2 Increased to 2.3 μg / cm 2 The reason is that there is no antibacterial agent coating and fixing structure in the matrix, and a large amount of trace free silver ions (raw material impurities) are released after contact with the outside world.

[0121] In summary, the multifunctional interface enhancer (fluorinated polyhedral oligomeric silsesquioxane) and the composite antibacterial agent (silver@zinc oxide / graphene oxide composite antibacterial agent) are the core components of this solution. The former constructs a fluorine-based network, preventing the antibacterial agent from agglomerating and detaching, enhancing mechanical and heat resistance, and reducing silver ion precipitation; the latter provides silver ions and hydroxyl radicals to achieve highly efficient antibacterial activity. The synergistic effect of these two components results in an antibacterial rate exceeding 99.5%, stable performance after aging, and extremely low silver ion precipitation.

[0122] The above embodiments are only used to illustrate the technical solutions of the present invention, and are not intended to limit it. Although the present invention has been described in detail with reference to the foregoing embodiments, those skilled in the art should understand that modifications can still be made to the technical solutions described in the foregoing embodiments, or equivalent substitutions can be made to some of the technical features. Such modifications or substitutions do not cause the essence of the corresponding technical solutions to deviate from the spirit and scope of the technical solutions of the embodiments of the present invention.

Claims

1. An antibacterial PVC sheet material, characterized by, The composition of the antibacterial PVC plate includes, in parts by weight, base resin 95-105, heat-resistant reinforcing agent 6-14, fluorine-based functional agent 1.5-4.5, multifunctional interface reinforcing agent 2-6, composite antibacterial agent 1.5-5, interface compatibilizer 1.3-4.5, filler 9-18, stabilizer 2.5-4.5, lubricant 1.3-3, antioxidant 0.4-0.9, and ultraviolet absorber 0.3-0.

8.

2. The antibacterial PVC sheet according to claim 1, characterized in that, The base resin is SG-5 type polyvinyl chloride resin; The heat-resistant reinforcing agent is composed of chlorinated polyvinyl chloride and polysulfone at a mass ratio of 0.8:1-4.5:1; The fluorine-based functional agent is polyvinylidene fluoride powder with a particle size of 0.5-2 μm; The interface compatibilizer is composed of maleic anhydride grafted ethylene-vinyl acetate copolymer with a grafting rate of 1.5%-3% and maleic anhydride grafted polypropylene with a grafting rate of 2%-4% at a mass ratio of 0.4:1-5:1; The filler is composed of light calcium carbonate and nano-silicon dioxide at a mass ratio of 2.67:1-15:1, and the surface of the nano-silicon dioxide is modified by silane coupling agent; The stabilizer is calcium-zinc composite stabilizer doped with rare earth lanthanum ions; The lubricant is composed of pentaerythritol stearate and zinc stearate at a mass ratio of 0.67:1-3.6:1; The antioxidant is antioxidant 168; The ultraviolet absorber is ultraviolet absorber UV-531.

3. The antibacterial PVC sheet according to claim 2, characterized in that, The chlorine content of chlorinated polyvinyl chloride in the heat-resistant reinforcing agent is 63%-67%; the fineness of light calcium carbonate in the filler is 1250 mesh, and the particle size of nano-silicon dioxide is 50 nm; and the content of rare earth lanthanum ions in the stabilizer is 2%-5%.

4. The antibacterial PVC sheet according to claim 2, characterized by, The composition of the multifunctional interface reinforcing agent includes, in parts by weight, octavinyl-polyhedral oligomeric silesquioxane 4-6, 1H,1H,2H,2H-perfluorooctylthiol 8-12, azobisisobutyronitrile 0.13-0.2, and toluene 95-105.

5. The antibacterial PVC sheet according to claim 4, characterized in that, The preparation method of the multifunctional interface reinforcing agent includes the following steps: 1) A 500 mL dry three-necked flask is selected, equipped with a stirrer, a reflux condenser, and a nitrogen inlet tube, and the flask is placed in a constant temperature water bath. Octavinyl-polyhedral oligomeric silesquioxane and toluene are added to the three-necked flask, and stirred at a speed of 300-400 r / min at room temperature for 30-40 min until the octavinyl-polyhedral oligomeric silesquioxane is completely dissolved to form a transparent solution; 2) 1H,1H,2H,2H-perfluorooctylthiol and azobisisobutyronitrile are added to the transparent solution in sequence, and continue to be stirred at a speed of 300-400 r / min for 15-20 min to mix the materials uniformly. Then nitrogen is introduced at a rate of 100-150 mL / min to replace the air in the flask for 3 times, each time for 10 min. After the replacement is completed, the nitrogen pressure is maintained at 0.01-0.02 MPa, and the temperature of the constant temperature water bath is increased to 70-80℃ at a rate of 5℃ / min. The reflux is started, and the reaction is carried out for 24-48 h. 3) After the reaction is completed, the heating and stirring are turned off, the reaction solution is cooled to room temperature, the cooled reaction solution is slowly dropped into 5 times the volume of ice methanol at 0-5°C, stirring is maintained at 200-300 r / min during the dropping, after the white precipitate is precipitated, the precipitate is collected by Buchner funnel filtration, the precipitate is washed repeatedly with ice methanol for 3-5 times, and the unreacted 1H, 1H, 2H, 2H-perfluorooctyl mercaptan and azobisisobutyronitrile are removed; 4) The precipitate treated in step 3) is placed in a vacuum oven, the temperature is set to 50°C, the vacuum degree is set to -0.095 MPa to -0.098 MPa, and the drying is performed for 24 h to obtain the multifunctional interface reinforcing agent.

6. The antibacterial PVC sheet according to claim 5, characterized in that, In step 2), the reaction process needs to be sampled every 3 hours, and the disappearance of the ethylene group characteristic peak (1630 cm -1 ) is monitored by infrared spectrum to determine the reaction endpoint; in step 3), the amount of ice-cold methanol used for washing the precipitate is twice the wet weight of the precipitate.

7. The antibacterial PVC sheet according to claim 2, characterized by, The composite antibacterial agent comprises, in parts by weight, 0.8-1.2 parts of graphene oxide, 95-105 parts of deionized water, 2-4 parts of silver nitrate, 0.8-1.6 parts of sodium borohydride, 2-4 parts of zinc nitrate, 10-15 parts of ammonia water with a mass concentration of 25%-28%, and 48-52 parts of ethanol.

8. The antibacterial PVC sheet according to claim 7, characterized by, The preparation method of the composite antibacterial agent comprises the following steps: a. The silver nitrate, sodium borohydride and zinc nitrate are respectively dissolved in deionized water to prepare 0.1-0.3 mol / L, 0.09-0.11 mol / L and 0.2-0.5 mol / L solutions respectively; b. The graphene oxide is added to the deionized water and placed in an ultrasonic dispersing instrument, the power is set to 300-500 W, and the ultrasonic time is set to 30-60 min, during which the instrument is stopped every 15 min for 5 min, and after the ultrasonic is completed, the graphene oxide dispersion liquid is obtained; c. The graphene oxide dispersion liquid is transferred to a 250 mL three-necked flask, stirring is maintained at a speed of 250-300 r / min at room temperature, the silver nitrate solution is added at a uniform speed within 15-20 min, after the addition is completed, the stirring is continued for 30 min, then the sodium borohydride solution is added at a uniform speed within 20-30 min, after the addition is completed, the room temperature reaction is performed for 1-2 h, and the silver / graphene oxide dispersion liquid is obtained; d. The zinc nitrate solution is added to the silver / graphene oxide dispersion liquid and stirred for 10-15 min, the ammonia water is added at a dropping speed of 1-2 mL / min to adjust the pH value of the solution to 8-9, then the three-necked flask is placed in a constant-temperature water bath, the temperature is raised to 60-80°C, the stirring is performed at a speed of 200-250 r / min, and the reaction is performed for 2-4 h, then the temperature is raised to 100-120°C, and the temperature is kept for 1-2 h; e. The dispersion liquid obtained in step d is transferred to a centrifuge tube and placed in a high-speed centrifuge, the speed is set to 8000-10000 r / min, the centrifugation time is set to 10-15 min, the precipitate is collected, the precipitate is washed with deionized water for 3-4 times until the pH value of the washing liquid is 7, the precipitate is washed once with ethanol to remove the residual water on the surface, finally the washed precipitate is placed in a vacuum oven, the temperature is set to 50-60°C, the vacuum degree is set to -0.095 MPa to -0.098 MPa, the drying is performed for 12-24 h, the dried product is crushed by a planetary ball mill, and the crushed product is sieved through a 200-mesh sieve to obtain the composite antibacterial agent. After each time of washing with deionized water, centrifugal treatment is needed at a speed of 4900-5000 r / min for 5 min.

9. A method of producing the antibacterial PVC sheet according to any one of claims 2 to 8, characterized by, The method comprises the following steps: S1, polyvinyl chloride resin, chlorinated polyvinyl chloride, polysulfone, polyvinylidene fluoride powder, multifunctional interface reinforcing agent, composite antibacterial agent, maleic anhydride grafted ethylene-vinyl acetate copolymer, maleic anhydride grafted polypropylene, light calcium carbonate, nano silicon dioxide, calcium-zinc composite stabilizer, pentaerythritol stearate, zinc stearate, antioxidant 168, and ultraviolet absorber UV-531 are sequentially added into a high-speed mixer, the mixer speed is set to 1100-1300 r / min, the temperature is raised to 95-105℃, and the mixture is kept for 12-18 min; after the mixing is completed, the heating is turned off, and the stirring is continued until the material temperature drops to room temperature, and the mixture is ready for use; S2, the mixed material is added into a double-screw extruder, and the temperature gradient of the extruder is set as follows: Zone 1: 160-170℃, zone 2: 170-180℃, and zone 3: 180-190℃; The screw speed is adjusted to 20-30 r / min, and the feeding rate is 10-15 kg / h; after the material is melted, mixed and sheared by the extruder, it is extruded into a strip shape by a die, cooled to below 40℃ by a cooling tank, and then pelletized by a pelletizer to obtain antibacterial polyvinyl chloride composite masterbatch; S3, the antibacterial polyvinyl chloride composite masterbatch is added into a calender, the front roller temperature is set to 185-195℃, the rear roller temperature is set to 180-190℃, the roller speed ratio of the front roller to the rear roller is 1:1.4-1:1.6, and the roller spacing is adjusted according to the product thickness; the calender is turned on, the masterbatch is put between the rollers, and the masterbatch is preheated, plasticized and calendered into a continuous sheet; the sheet material is pulled by a pulling machine to a cooling roller group and cooled to below 45℃, and finally cut by a cutting machine according to the set size to obtain antibacterial polyvinyl chloride plate finished product.

10. The method of claim 9, wherein the method further comprises the step of adding a stabilizer to the PVC resin. 10 During the stirring process in the temperature keeping stage of step S1, the material temperature is measured every 3 min by an infrared temperature measuring instrument to ensure that the material temperature is uniformly controlled within the range of 95-105℃.

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