Antibacterial pet sheet and method for preparing the same

Abstract

The application discloses an antibacterial PET sheet and a preparation method thereof, and belongs to the technical field of high polymer materials. The antibacterial PET sheet comprises the following components in parts by weight: 60-80 parts of PET resin, 8-10 parts of a compatilizer, 10-20 parts of modified glass fiber, 5-10 parts of a composite antibacterial agent, 1-2 parts of a lubricant and 1-2 parts of an antioxidant. The antibacterial PET sheet prepared by the method has good long-acting antibacterial and mechanical and flame-retardant properties.

Description

Technical Field

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

[0002] PET is short for polyethylene terephthalate, a thermoplastic, highly crystalline polymer. PET plastic has excellent optical properties, weather resistance, abrasion resistance, dimensional stability, electrical insulation, high strength, good transparency, non-toxicity, impermeability, light weight, and high production efficiency. Therefore, it is widely used in food packaging, daily chemical products, medical devices, and electronic appliances.

[0003] However, PET material itself does not possess antibacterial properties and is prone to the growth of bacteria, mold, and other microorganisms in humid environments. This limits its application in fields with high cleanliness requirements, such as medical and hygiene products and high-end food packaging. To impart antibacterial properties to PET material, antibacterial agents are typically added. While traditional inorganic antibacterial agents (such as nano-silver and nano-zinc oxide) have good antibacterial effects, they tend to agglomerate within the PET matrix, exhibiting poor dispersibility and affecting the material's transparency and mechanical properties.

[0004] Chinese patent document CN107286601A discloses a long-lasting antibacterial PET masterbatch and its preparation method. The raw material formula of the antibacterial PET masterbatch, by weight percentage, is: 3-8% Unined RM antibacterial agent, 0.5% polyethylene wax, 0.2% coupling agent, and the balance being PET plastic resin. This invention's antibacterial masterbatch uses multiple compounds, exhibiting good dispersibility and compatibility when combined with PET plastic resin. When added to polyester plastics such as PET and PBT, it demonstrates excellent aging resistance and better mechanical properties, significantly extending service life. It also possesses antibacterial properties against common pathogens, inhibits drug-resistant pathogens, is highly efficient and durable, and washable, purifying the environment, eliminating odors, and providing self-cleaning and health benefits. It does not pollute the environment and has no side effects on the human body, thus providing greater health benefits. However, the antibacterial agent in this invention is mainly added to the PET resin matrix through blending, resulting in weak interfacial bonding with the resin matrix. Therefore, the mechanical properties and flame retardant properties of the obtained antibacterial PET masterbatch require further improvement. Summary of the Invention

[0005] The main objective of this invention is to provide an antibacterial PET sheet and its preparation method. The antibacterial PET sheet prepared by this invention has excellent flame retardant, antibacterial and mechanical properties.

[0006] To achieve the above objectives, the present invention proposes an antibacterial PET sheet comprising the following components by weight: 60-80 parts PET resin, 8-10 parts compatibilizer, 10-20 parts modified glass fiber, 5-10 parts composite antibacterial agent, 1-2 parts lubricant, and 1-2 parts antioxidant.

[0007] Preferably, the compatibilizer is ethylene-methyl acrylate-glycidyl methacrylate.

[0008] Preferably, the modified glass fiber is prepared by the following method:

[0009] Glass fibers were soaked in sodium hydroxide aqueous solution, then removed, washed, and dried. Dopamine was added to Tris-HCl buffer solution, and the reaction was carried out at room temperature. The reaction product was centrifuged, washed, and vacuum dried to obtain coated modified glass fibers. The coated modified glass fibers were added to N,N-dimethylformamide, and isophorone diisocyanate was added dropwise. After the addition was complete, linolenic acid alcohol was added and stirred evenly. Then, dibutyltin dilaurate was added as a catalyst, and the reaction was heated under nitrogen protection. After the reaction was completed, the reaction mixture was cooled to room temperature, filtered, washed, and dried to obtain modified glass fibers.

[0010] More preferably, the mass ratio of the glass fiber, dopamine, isophorone diisocyanate, linolenic acid alcohol, and dibutyltin dilaurate is 1:2-4:1.5-2.5:0.8-1.2:0.2-0.4; the heating reaction temperature is 60-70℃, and the reaction time is 2-4 hours.

[0011] The preparation of the modified glass fiber of this invention begins with etching the glass fiber using an aqueous sodium hydroxide solution. This not only increases the number of hydroxyl groups but also increases the surface roughness and specific surface area, providing more adhesion space for subsequent reactants. Then, polydopamine is polymerized in situ on the glass fiber surface to coat and modify it. The surface of the antibacterial polydopamine film is rich in active groups such as hydroxyl and amine groups. On the one hand, this provides anchoring sites for subsequent reactions; on the other hand, during subsequent processing, it easily cross-links with the compatibilizer ethylene-methyl acrylate-glycidyl methacrylate, thereby strengthening the glass fiber. The interfacial bonding force of the fibers allows for more uniform stress distribution, thereby improving the mechanical properties and antibacterial properties of PET sheets. Finally, isocyanate groups are introduced into the coated modified glass fibers by reacting isophorone diisocyanate with some of the active groups in polydopamine. These isocyanate groups react with the hydroxyl groups on linoleic acid, introducing flexible chain segments onto the surface of the polydopamine-coated glass fibers. When the modified glass fibers are mixed into the molten PET resin, the long chains of linoleic acid can extend into the PET matrix, physically entangle and penetrate with the surrounding PET molecular chains, forming a strong whole and further enhancing the interfacial bonding force.

[0012] Preferably, the preparation method of the composite antibacterial agent is as follows:

[0013] 1) Add nano-zirconium phosphate and tetrabutyl titanate to an ethanol aqueous solution, mix and stir evenly, then add ammonia to adjust the pH of the system to 9-10, carry out hydrothermal reaction, filter and collect the solid, wash and calcine to obtain nano-zirconium phosphate composite.

[0014] 2) Add the nano-zirconium phosphate composite to an ethanol aqueous solution, add vinyltriethoxysilane, and heat to react to obtain the vinyl nano-zirconium phosphate composite;

[0015] 3) Add 4-amino-3-hydrazino-5-mercapto-1,2,4-triazole to N,N-dimethylformamide, add vinyl nano-zirconium phosphate composite and 2,2-dimethoxy-2-phenylacetophenone, react under ultraviolet light, filter and collect the solid after the reaction, wash and dry it, add it to water, add zinc acetate dihydrate and mix well, then add oxalic acid ethanol solution, stir the reaction, centrifuge and collect the precipitate, and calcine to obtain the composite antibacterial agent.

[0016] More preferably, in step 1), the mass ratio of nano-zirconium phosphate to tetrabutyl titanate is 3-5:1; the hydrothermal reaction temperature is 130-140℃ and the time is 6-8h; the calcination temperature is 500-700℃ and the calcination time is 1-2h.

[0017] More preferably, in step 2), the mass ratio of the nano-zirconium phosphate composite to vinyltriethoxysilane is 10-20:1-3; the heating temperature is 40-60℃, and the heating time is 4-6h.

[0018] More preferably, in step 3), the mass ratio of 4-amino-3-hydrazino-5-mercapto-1,2,4-triazole, vinyl nano-zirconium phosphate complex, and zinc acetate dihydrate is 2-4:2-4:1-3.

[0019] The preparation of the composite antibacterial agent of this invention first involves the in-situ generation of titanium dioxide on the surface of flame retardant nano-zirconium phosphate via a hydrothermal method. This hydrothermal reaction strengthens the bond between titanium dioxide and nano-zirconium phosphate, preventing agglomeration and improving the antibacterial and flame-retardant properties of the material. Next, the nano-zirconium phosphate composite undergoes surface treatment to introduce carbon-carbon double bonds. Then, the vinyl nano-zirconium phosphate composite is reacted with 4-amino-3-hydrazino-5-mercapto-1,2,4-triazole to generate the 4-amino-3-hydrazino-5-mercapto-1,2,4-triazole. Introducing 4-triazole into the nano-zirconium phosphate composite has two advantages. First, the amino groups on its molecule can cross-link with the compatibilizer ethylene-methyl acrylate-glycidyl methacrylate during subsequent processing, thereby enhancing the interfacial bonding force of the composite antibacterial agent. Second, the numerous heteroatoms on 4-amino-3-hydrazino-5-mercapto-1,2,4-triazole can coordinate with zinc ions, enhancing the bonding force between zinc ions and the nano-zirconium phosphate composite. After calcination, zinc oxide is tightly bonded to the nano-zirconium phosphate composite, improving the antibacterial and flame-retardant properties of PET sheets.

[0020] Preferably, the lubricant is at least one of calcium stearate, zinc stearate, barium stearate, polyethylene wax, and butyl stearate.

[0021] Preferably, the antioxidant is one of pentaerythritol tetrakis[β-(3,5-di-tert-butyl-4-hydroxyphenyl)propionate] or dilauryl thiodipropionate.

[0022] This invention also discloses a method for preparing the above-mentioned antibacterial PET sheet, comprising the following steps:

[0023] Weigh each component according to the formula, dry the PET resin and mix it evenly with compatibilizer, modified glass fiber, composite antibacterial agent, lubricant and antioxidant to obtain a mixture. Melt extrusion granulation of the mixture at 250-270℃ to obtain PET composite material. Add the PET composite material to a twin-screw extruder for melt plasticization, extrusion, rolling traction and cooling to obtain antibacterial PET sheet.

[0024] Compared with the prior art, the beneficial effects of the present invention are as follows:

[0025] (1) This invention provides an antibacterial PET sheet, which uses PET resin as the base material and is compounded with functional additives such as compatibilizer, lubricant, and antioxidant. Modified glass fiber and composite antibacterial agent are also introduced. The antibacterial PET sheet prepared has good long-lasting antibacterial, mechanical and flame-retardant properties, enabling it to be applied to more complex application scenarios.

[0026] (2) The present invention enhances the interfacial bonding force of the glass fiber by adding modified glass fiber to the antibacterial PET sheet, which can cross-link with the compatibilizer ethylene-methyl acrylate-glycidyl methacrylate, so that the stress is more evenly distributed, thereby improving the mechanical properties and antibacterial properties of the PET sheet; when the modified glass fiber is mixed into the molten PET resin, the flexible long chain of linoleic acid on its surface can extend into the PET matrix, physically entangle and penetrate with the surrounding PET molecular chains, forming a strong whole, further enhancing the interfacial bonding force;

[0027] (3) The composite antibacterial agent added to the antibacterial PET sheet in this invention can improve the long-lasting antibacterial and flame retardant properties of the material. Furthermore, the amino groups on its molecules can cross-link with the compatibilizer ethylene-methyl acrylate-glycidyl methacrylate during subsequent processing, thereby enhancing the interfacial bonding force of the nano-zirconium phosphate composite. On the other hand, the numerous heteroatoms on 4-amino-3-hydrazino-5-mercapto-1,2,4-triazole can coordinate with zinc ions, enhancing the bonding force between zinc ions and the nano-zirconium phosphate composite. After calcination, zinc oxide is tightly bonded to the nano-zirconium phosphate composite, improving the antibacterial and flame retardant properties of the PET sheet. Detailed Implementation

[0028] To avoid unnecessary details, unless otherwise specified, all items used in the following examples are commercially available products, and all methods used are conventional methods unless otherwise specified.

[0029] The sources of some of the raw materials used in this invention are as follows:

[0030] Glass fiber, 3-15mm, purchased from Wuhe County Weijia Composite Materials Co., Ltd.

[0031] Nano-zirconium phosphate, with an average particle size of 0.5-2 μm, was purchased from Jining Fangyu Chemical Co., Ltd.

[0032] PET resin, model 3541, purchased from Condis Chemical (Hubei) Co., Ltd.

[0033] Example 1

[0034] A method for preparing an antibacterial PET sheet includes the following steps:

[0035] 70g of dried PET resin was mixed with 9g of ethylene-methyl acrylate-glycidyl methacrylate, 15g of modified glass fiber, 8.5g of composite antibacterial agent, 1.6g of calcium stearate, and 1.4g of dilauryl thiodipropionate to obtain a mixture. The mixture was melt-extruded and granulated at 260℃ to obtain a PET composite material. The PET composite material was added to a twin-screw extruder for melt plasticization, extrusion, rolling traction, and cooling and shaping to obtain antibacterial PET sheets.

[0036] The modified glass fiber is prepared as follows:

[0037] 10g of glass fiber was soaked in 1mol / L sodium hydroxide aqueous solution for 2h, then washed until the pH of the filtrate was 7. After drying, it was added to 300mL of Tris-HCl buffer solution with pH 9 with 30g of dopamine. Oxygen was introduced and the reaction was carried out at room temperature for 2h. The reaction product was centrifuged, washed, and vacuum dried to obtain coated modified glass fiber. The coated modified glass fiber was added to 150mL of N,N-dimethylformamide, and 20g of isophorone diisocyanate was added dropwise. After the addition was complete, 10g of linolenic acid alcohol was added and stirred evenly. Then, 3g of dibutyltin dilaurate was added as a catalyst, and the reaction was heated at 60℃ for 3h under nitrogen protection. After the reaction was completed, the reaction mixture was cooled to room temperature, filtered, and the solid was collected, washed, and dried to obtain modified glass fiber.

[0038] The preparation method of the composite antibacterial agent is as follows:

[0039] 1) Add 40g of nano-zirconium phosphate and 10g of tetrabutyl titanate to 500mL of 50wt% ethanol aqueous solution, mix and stir evenly, then add 25wt% ammonia water to adjust the pH of the system to 9-10, and then carry out hydrothermal reaction at 140℃ for 7h. After the reaction is completed, filter and collect the solid, wash it, and calcine it at 600℃ for 2h to obtain nano-zirconium phosphate composite.

[0040] 2) Add 30g of nano-zirconium phosphate composite to 300mL of 50wt% ethanol aqueous solution, add 4g of vinyltriethoxysilane, heat at 50℃ for 5h, filter, collect the solid, wash and dry to obtain vinyl nano-zirconium phosphate composite.

[0041] 3) Add 15g of 4-amino-3-hydrazino-5-mercapto-1,2,4-triazole to 200mL of N,N-dimethylformamide, add 15g of vinyl nano-zirconium phosphate composite and 0.6g of 2,2-dimethoxy-2-phenylacetophenone, and react under 365nm ultraviolet light for 30min. After the reaction, filter and collect the solid, wash and dry it, and add it to 200mL of water. Add 10g of zinc acetate dihydrate and mix well. Then add 40mL of ethanol solution containing 5g of oxalic acid. Stir and react at room temperature for 30min. Centrifuge and collect the precipitate. Calcine at 550℃ for 2h to obtain the composite antibacterial agent.

[0042] Example 2

[0043] A method for preparing an antibacterial PET sheet includes the following steps:

[0044] After drying 60g of PET resin, it is mixed with 8g of ethylene-methyl acrylate-glycidyl methacrylate, 10g of modified glass fiber, 5g of composite antibacterial agent, 1g of calcium stearate, and 1g of dilauryl thiodipropionate to obtain a mixture. The mixture is then melt-extruded and granulated at 250℃ to obtain a PET composite material. The PET composite material is then added to a twin-screw extruder for melt plasticization, extrusion, rolling traction, and cooling and shaping to obtain antibacterial PET sheets.

[0045] The modified glass fiber is prepared as follows:

[0046] 10g of glass fiber was soaked in 1mol / L sodium hydroxide aqueous solution for 2h, then washed until the pH of the filtrate was 7. After drying, it was added to 300mL of Tris-HCl buffer solution with pH 9 and 20g of dopamine. Oxygen was introduced and the reaction was carried out at room temperature for 2h. The reaction product was centrifuged, washed, and vacuum dried to obtain coated modified glass fiber. The coated modified glass fiber was added to 150mL of N,N-dimethylformamide, and 15g of isophorone diisocyanate was added dropwise. After the addition was complete, 8g of linolenic acid alcohol was added and stirred evenly. Then, 2g of dibutyltin dilaurate was added as a catalyst, and the reaction was heated at 70℃ for 2h under nitrogen protection. After the reaction was completed, the reaction mixture was cooled to room temperature, filtered, and the solid was collected, washed, and dried to obtain modified glass fiber.

[0047] The preparation method of the composite antibacterial agent is as follows:

[0048] 1) Add 30g of nano-zirconium phosphate and 10g of tetrabutyl titanate to 500mL of 50wt% ethanol aqueous solution, mix and stir evenly, then add 25wt% ammonia water to adjust the pH of the system to 10, and then carry out hydrothermal reaction at 140℃ for 7h. After the reaction is completed, filter and collect the solid, wash it, and calcine it at 600℃ for 2h to obtain nano-zirconium phosphate composite.

[0049] 2) Add 20g of nano-zirconium phosphate composite to 300mL of 50wt% ethanol aqueous solution, add 2g of vinyltriethoxysilane, heat and react at 50℃ for 5h, filter, collect the solid, wash and dry to obtain vinyl nano-zirconium phosphate composite.

[0050] 3) Add 10g of 4-amino-3-hydrazino-5-mercapto-1,2,4-triazole to 200mL of N,N-dimethylformamide, add 10g of vinyl nano-zirconium phosphate composite and 0.5g of 2,2-dimethoxy-2-phenylacetophenone, and react under 365nm ultraviolet light for 30min. After the reaction, filter and collect the solid, wash and dry it, and add it to 200mL of water. Add 8g of zinc acetate dihydrate and mix well. Then add 40mL of ethanol solution containing 4g of oxalic acid. Stir and react at room temperature for 30min. Centrifuge and collect the precipitate. Calcine at 550℃ for 2h to obtain the composite antibacterial agent.

[0051] Example 3

[0052] A method for preparing an antibacterial PET sheet includes the following steps:

[0053] After drying 80g of PET resin, it is mixed with 10g of ethylene-methyl acrylate-glycidyl methacrylate, 20g of modified glass fiber, 10g of composite antibacterial agent, 2g of calcium stearate, and 2g of dilauryl thiodipropionate to obtain a mixture. The mixture is then melt-extruded and granulated at 270℃ to obtain a PET composite material. The PET composite material is then added to a twin-screw extruder for melt plasticization, extrusion, rolling traction, and cooling and shaping to obtain antibacterial PET sheets.

[0054] The modified glass fiber is prepared as follows:

[0055] 10g of glass fiber was soaked in 1mol / L sodium hydroxide aqueous solution for 2h, then washed until the pH of the filtrate was 7. After drying, it was added to 300mL of Tris-HCl buffer solution with pH 9 and 40g of dopamine. Oxygen was introduced and the reaction was carried out at room temperature for 2h. The reaction product was centrifuged, washed, and vacuum dried to obtain coated modified glass fiber. The coated modified glass fiber was added to 150mL of N,N-dimethylformamide, and 25g of isophorone diisocyanate was added dropwise. After the addition was complete, 12g of linolenic acid alcohol was added and stirred evenly. Then, 4g of dibutyltin dilaurate was added as a catalyst, and the reaction was heated at 70℃ for 4h under nitrogen protection. After the reaction was completed, the reaction mixture was cooled to room temperature, filtered, and the solid was collected, washed, and dried to obtain modified glass fiber.

[0056] The preparation method of the composite antibacterial agent is as follows:

[0057] 1) Add 50g of nano-zirconium phosphate and 10g of tetrabutyl titanate to 500mL of 50wt% ethanol aqueous solution, mix and stir evenly, then add 25wt% ammonia water to adjust the pH of the system to 10, and then carry out hydrothermal reaction at 140℃ for 7h. After the reaction is completed, filter and collect the solid, wash it, and calcine it at 600℃ for 2h to obtain nano-zirconium phosphate composite.

[0058] 2) Add 40g of nano-zirconium phosphate composite to 500mL of 50wt% ethanol aqueous solution, add 6g of vinyltriethoxysilane, heat at 50℃ for 5h, filter, collect the solid, wash and dry to obtain vinyl nano-zirconium phosphate composite.

[0059] 3) Add 20g of 4-amino-3-hydrazino-5-mercapto-1,2,4-triazole to 200mL of N,N-dimethylformamide, add 20g of vinyl nano-zirconium phosphate composite and 0.8g of 2,2-dimethoxy-2-phenylacetophenone, and react under 365nm ultraviolet light for 30min. After the reaction, filter and collect the solid, wash and dry it, and add it to 200mL of water. Add 13g of zinc acetate dihydrate and mix well. Then add 40mL of ethanol solution containing 7g of oxalic acid. Stir and react at room temperature for 30min. Centrifuge and collect the precipitate. Calcine at 550℃ for 2h to obtain the composite antibacterial agent.

[0060] Comparative Example 1

[0061] A method for preparing an antibacterial PET sheet includes the following steps:

[0062] 70g of dried PET resin was mixed with 9g of ethylene-methyl acrylate-glycidyl methacrylate, 15g of glass fiber, 8.5g of composite antibacterial agent, 1.6g of calcium stearate, and 1.4g of dilauryl thiodipropionate to obtain a mixture. The mixture was melt-extruded and granulated at 260℃ to obtain a PET composite material. The PET composite material was added to a twin-screw extruder for melt plasticization, extrusion, rolling traction, and cooling and shaping to obtain antibacterial PET sheets.

[0063] The preparation method of the composite antibacterial agent is as follows:

[0064] 1) Add 40g of nano-zirconium phosphate and 10g of tetrabutyl titanate to 500mL of 50wt% ethanol aqueous solution, mix and stir evenly, then add 25wt% ammonia water to adjust the pH of the system to 9-10, and then carry out hydrothermal reaction at 140℃ for 7h. After the reaction is completed, filter and collect the solid, wash it, and calcine it at 600℃ for 2h to obtain nano-zirconium phosphate composite.

[0065] 2) Add 30g of nano-zirconium phosphate composite to 300mL of 50wt% ethanol aqueous solution, add 4g of vinyltriethoxysilane, heat at 50℃ for 5h, filter, collect the solid, wash and dry to obtain vinyl nano-zirconium phosphate composite.

[0066] 3) Add 15g of 4-amino-3-hydrazino-5-mercapto-1,2,4-triazole to 200mL of N,N-dimethylformamide, add 15g of vinyl nano-zirconium phosphate composite and 0.6g of 2,2-dimethoxy-2-phenylacetophenone, react under 365nm ultraviolet light for 30min, filter and collect the solid, wash and dry to obtain the composite antibacterial agent.

[0067] Comparative Example 2

[0068] A method for preparing an antibacterial PET sheet includes the following steps:

[0069] 70g of dried PET resin was mixed with 9g of ethylene-methyl acrylate-glycidyl methacrylate, 15g of modified glass fiber, 8.5g of nano-zirconium phosphate composite, 1.6g of calcium stearate, and 1.4g of dilauryl thiodipropionate to obtain a mixture. The mixture was melt-extruded and granulated at 260℃ to obtain a PET composite material. The PET composite material was added to a twin-screw extruder for melt plasticization, extrusion, rolling traction, and cooling and shaping to obtain antibacterial PET sheets.

[0070] The modified glass fiber is prepared as follows:

[0071] 10g of glass fiber was soaked in 1mol / L sodium hydroxide aqueous solution for 2h, then washed until the pH of the filtrate was 7. After drying, it was added to 300mL of Tris-HCl buffer solution with pH 9 with 30g of dopamine. Oxygen was introduced and the reaction was carried out at room temperature for 2h. The reaction product was centrifuged, washed, and vacuum dried to obtain coated modified glass fiber. The coated modified glass fiber was added to 150mL of N,N-dimethylformamide, and 20g of isophorone diisocyanate was added dropwise. After the addition was complete, 10g of linolenic acid alcohol was added and stirred evenly. Then, 3g of dibutyltin dilaurate was added as a catalyst, and the reaction was heated at 60℃ for 3h under nitrogen protection. After the reaction was completed, the reaction mixture was cooled to room temperature, filtered, and the solid was collected, washed, and dried to obtain modified glass fiber.

[0072] The preparation method of the nano-zirconium phosphate composite is as follows:

[0073] 40g of nano-zirconium phosphate and 10g of tetrabutyl titanate were added to 500mL of 50wt% ethanol aqueous solution, mixed and stirred evenly, and then 25wt% ammonia was added to adjust the pH of the system to 9-10. Then, a hydrothermal reaction was carried out at 140℃ for 7h. After the reaction was completed, the solid was collected by filtration and washed, and then calcined at 600℃ for 2h to obtain nano-zirconium phosphate composite.

[0074] Comparative Example 3

[0075] A method for preparing an antibacterial PET sheet includes the following steps:

[0076] 70g of dried PET resin was mixed with 9g of ethylene-methyl acrylate-glycidyl methacrylate, 15g of modified glass fiber, 8.5g of composite antibacterial agent, 1.6g of calcium stearate, and 1.4g of dilauryl thiodipropionate to obtain a mixture. The mixture was melt-extruded and granulated at 260℃ to obtain a PET composite material. The PET composite material was added to a twin-screw extruder for melt plasticization, extrusion, rolling traction, and cooling and shaping to obtain antibacterial PET sheets.

[0077] The modified glass fiber is prepared as follows:

[0078] 10g of glass fiber was soaked in 1mol / L sodium hydroxide aqueous solution for 2h, then washed until the pH of the filtrate was 7. After drying, it was added to 300mL of Tris-HCl buffer solution with pH 9 with 30g of dopamine. Oxygen was introduced and the reaction was carried out at room temperature for 2h. The reaction product was centrifuged, washed, and vacuum dried to obtain coated modified glass fiber. The coated modified glass fiber was added to 150mL of N,N-dimethylformamide, and 20g of isophorone diisocyanate was added dropwise. After the addition was complete, 10g of linolenic acid alcohol was added and stirred evenly. Then, 3g of dibutyltin dilaurate was added as a catalyst, and the reaction was heated at 60℃ for 3h under nitrogen protection. After the reaction was completed, the reaction mixture was cooled to room temperature, filtered, and the solid was collected, washed, and dried to obtain modified glass fiber.

[0079] The preparation method of the composite antibacterial agent is as follows:

[0080] 1) Add 40g of nano-zirconium phosphate and 10g of tetrabutyl titanate to 500mL of 50wt% ethanol aqueous solution, mix and stir evenly, then add 25wt% ammonia water to adjust the pH of the system to 9-10, and then carry out hydrothermal reaction at 140℃ for 7h. After the reaction is completed, filter and collect the solid, wash it, and calcine it at 600℃ for 2h to obtain nano-zirconium phosphate composite.

[0081] 2) Add 30g of nano-zirconium phosphate composite to 300mL of 50wt% ethanol aqueous solution, add 4g of vinyltriethoxysilane, heat and react at 50℃ for 5h, filter to collect solids, wash and dry, add to 200mL of water, add 10g of zinc acetate dihydrate and mix well, then add 40mL of ethanol solution containing 5g of oxalic acid, stir and react at room temperature for 30min, centrifuge to collect precipitate, and calcine at 550℃ for 2h to obtain composite antibacterial agent.

[0082] Performance testing

[0083] Tensile strength test: In accordance with GB / T1040.2-2022 "Determination of tensile properties of plastics - Part 2: Test conditions for molded and extruded plastics", a dumbbell-shaped 50×10×4mm standard specimen was subjected to tensile test at a rate of 50mm / min under room temperature conditions.

[0084] Limiting oxygen index test: The test was conducted in accordance with GB / T 2406.2-2009 "Determination of flammability of plastics by oxygen index method - Part 2: Room temperature test".

[0085] Impact strength test: The test was conducted in accordance with GB / T1843-2008 "Determination of Impact Strength of Plastic Cantilever Beams" standard;

[0086] Antibacterial performance test: 1 ml of a 10% concentration was tested. 8 CFU / ml of Escherichia coli bacterial suspension was added dropwise to the surface of the antibacterial PET sheet samples prepared in Examples 1-3 after sterilization. The samples were incubated at 37°C for 8 hours. 20 μL of the cultured bacterial suspension was then transferred and evenly spread onto a solid culture medium. After incubation at 37°C for 24 hours, the number of colonies on the medium was counted. A blank experiment was also performed. The antibacterial rate was calculated using the following formula (Ⅰ):

[0087] Antibacterial rate = (AB) / A × 100%, Equation (I)

[0088] Where A represents the number of colonies in the blank experiment (number of colonies); and B represents the number of colonies in the sample group experiment (number of colonies).

[0089] The test results are shown in Table 1:

[0090] Table 1. Test results of antibacterial PET sheet performance

[0091]

[0092] As can be seen from the experimental results in Table 1, the antibacterial PET sheet obtained by this invention has excellent flame retardant, mechanical and antibacterial properties.

[0093] The above are merely preferred embodiments of the present invention and do not limit the patent scope of the present invention. Various modifications and variations can be made to the present invention by those skilled in the art. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of the present invention should be included within the patent protection scope of the present invention.

Claims

1. An antibacterial PET sheet, characterized in that, It includes the following components by weight: 60-80 parts PET resin, 8-10 parts compatibilizer, 10-20 parts modified glass fiber, 5-10 parts composite antibacterial agent, 1-2 parts lubricant, and 1-2 parts antioxidant. The modified glass fiber is prepared as follows: Glass fibers were soaked in sodium hydroxide aqueous solution, then washed, dried, and added to Tris-HCl buffer solution with dopamine. The reaction was carried out at room temperature. The reaction product was centrifuged, washed, and vacuum dried to obtain coated modified glass fibers. The coated modified glass fibers were added to N,N-dimethylformamide, and isophorone diisocyanate was added dropwise. After the addition was complete, linolenic acid alcohol was added and stirred evenly. Then, dibutyltin dilaurate was added as a catalyst, and the reaction was heated under nitrogen protection. After the reaction was completed, the reaction mixture was cooled to room temperature, filtered, washed, and dried to obtain modified glass fibers. The mass ratio of the glass fiber, dopamine, isophorone diisocyanate, linolenic acid alcohol, and dibutyltin dilaurate is 1:2-4:1.5-2.5:0.8-1.2:0.2-0.

4. The preparation method of the composite antibacterial agent is as follows: 1) Add nano-zirconium phosphate and tetrabutyl titanate to an ethanol aqueous solution, mix and stir evenly, then add ammonia to adjust the pH of the system to 9-10, carry out hydrothermal reaction, filter and collect the solid, wash and calcine to obtain nano-zirconium phosphate composite. 2) Add the nano-zirconium phosphate composite to an ethanol aqueous solution, add vinyltriethoxysilane, and heat to react to obtain the vinyl nano-zirconium phosphate composite; 3) Add 4-amino-3-hydrazino-5-mercapto-1,2,4-triazole to N,N-dimethylformamide, add vinyl nano-zirconium phosphate composite and 2,2-dimethoxy-2-phenylacetophenone, react under ultraviolet light, filter and collect the solid after the reaction, wash and dry it, add it to water, add zinc acetate dihydrate and mix well, then add oxalic acid ethanol solution, stir the reaction, centrifuge and collect the precipitate, and calcine to obtain the composite antibacterial agent.

2. The antibacterial PET sheet according to claim 1, characterized in that, The compatibilizer is ethylene-methyl acrylate-glycidyl methacrylate.

3. The antibacterial PET sheet according to claim 1, characterized in that: In step 1), the mass ratio of nano-zirconium phosphate to tetrabutyl titanate is 3-5:1; the hydrothermal reaction temperature is 130-140℃ and the time is 6-8h.

4. The antibacterial PET sheet according to claim 1, characterized in that: In step 2), the mass ratio of nano-zirconium phosphate composite to vinyltriethoxysilane is 10-20:1-3; the heating temperature is 40-60℃ and the heating time is 4-6h.

5. The antibacterial PET sheet according to claim 1, characterized in that: In step 3), the mass ratio of 4-amino-3-hydrazino-5-mercapto-1,2,4-triazole, vinyl nano-zirconium phosphate complex, and zinc acetate dihydrate is 2-4:2-4:1-3.

6. The antibacterial PET sheet according to claim 1, characterized in that, The lubricant is at least one of calcium stearate, zinc stearate, barium stearate, polyethylene wax, and butyl stearate.

7. A method for preparing the antibacterial PET sheet according to any one of claims 1-6, characterized in that, Includes the following steps: Weigh each component according to the formula, dry the PET resin and mix it evenly with compatibilizer, modified glass fiber, composite antibacterial agent, lubricant and antioxidant to obtain a mixture. Melt extrusion granulation of the mixture at 250-270℃ to obtain PET composite material. Add the PET composite material to a twin-screw extruder for melt plasticization, extrusion, rolling traction and cooling to obtain antibacterial PET sheet.

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