A bio-based antibacterial packaging material and its preparation method

Abstract

The present invention relates to the field of packaging materials, and particularly to a bio-based antibacterial packaging material and a preparation method thereof, which are used to solve the problem that the existing packaging materials have poor antibacterial performance, restricting their application in the field of antibacterial packaging. The preparation method reacts and modifies polylactic acid with doped zinc oxide, modified chitosan and multi-group siloxane to form an antibacterial substrate, endowing the bio-based antibacterial packaging material with a strong antibacterial ability, effectively inhibiting the growth of bacteria and molds. Moreover, polylactic acid is a bio-based material and can be naturally degraded, reducing environmental pollution, so that the prepared packaging material has excellent antibacterial performance, mechanical properties and biodegradability, and has broad application prospects in the fields of food, medicine and medical devices, which is of great significance for promoting the green development and sustainable development of the packaging industry.

Description

Technical Field

[0001] The present invention relates to the field of packaging materials, and particularly to a bio-based antibacterial packaging material and a preparation method thereof. Background Art

[0002] Traditional food packaging materials usually use petroleum-based raw materials, which are non-renewable and difficult to degrade, and are prone to causing serious environmental pollution. With the enhancement of environmental awareness and the increasing demand of consumers for healthy and safe food, traditional petroleum-based plastic packaging materials are difficult to meet the market demand due to their non-degradability and potential environmental pollution problems. Bio-based materials have gradually become a research hotspot in the field of packaging materials due to their renewable and degradable characteristics. Polylactic acid, as a bio-based plastic, has been widely studied due to its good biodegradability and biocompatibility. However, polylactic acid itself does not have antibacterial properties, resulting in poor antibacterial performance of the prepared packaging materials, which limits its application in the field of antibacterial packaging. Therefore, it is of great significance to develop a bio-based antibacterial packaging material and a preparation method thereof. Summary of the Invention

[0003] In order to overcome the above technical problems, the purpose of the present invention is to provide a bio-based antibacterial packaging material and a preparation method thereof, which solve the problem that the existing packaging materials have poor antibacterial performance and limit their application in the field of antibacterial packaging.

[0004] The purpose of the present invention can be achieved by the following technical solutions:

[0005] A bio-based antibacterial packaging material, comprising the following components in parts by weight:

[0006] 35-45 parts of antibacterial substrate, 7-14 parts of plasticizer, 5-11 parts of talc powder, 2-6 parts of titanium dioxide, 1.5-5.5 parts of compatibilizer, 1-3 parts of antioxidant, and 1-3 parts of ultraviolet absorber;

[0007] Wherein, the antibacterial substrate is prepared by the following steps:

[0008] Step s1: Add zinc acetate and deionized water into a three-necked flask equipped with a thermometer and a stirrer, stir and react at a temperature of 25-30 °C and a stirring rate of 300-400 r / min for 10-15 min, then adjust the pH to 10-11 with sodium hydroxide solution, and then continue to stir and react at a temperature of 50-55 °C for 30-40 min, and then continue to stir and react at a temperature of 160-170 °C for 10-12 h. After the reaction is completed, cool the reaction product to room temperature, then centrifuge, wash the precipitate with distilled water and absolute ethanol 2-3 times in sequence, and then place it in a vacuum drying oven and dry it at a temperature of 60-65 °C for 2-3 h to obtain nano-zinc oxide;

[0009] Step s2: Add nano-zinc oxide and deionized water into a three-necked flask equipped with a thermometer, a stirrer and a constant-pressure dropping funnel. Stir and react for 10 - 15 min under the conditions of a temperature of 25 - 30 °C and a stirring rate of 300 - 400 r / min. Then, while stirring, gradually add the silver nitrate solution dropwise, controlling the dropping rate at 1 - 2 drops / s. After the addition is complete, continue to stir and react for 1 - 1.5 h. Then, adjust the pH to 8 - 9 with sodium hydroxide solution. Then, raise the temperature to 80 - 85 °C and continue to stir and react for 4 - 5 h. After the reaction is completed, cool the reaction product to room temperature, then centrifuge, wash the precipitate with distilled water and absolute ethanol 2 - 3 times in sequence, and then place it in a vacuum drying oven and dry it for 2 - 3 h under the condition of a temperature of 60 - 65 °C to obtain doped zinc oxide;

[0010] Step s3: Add chitosan and acetic acid solution into a three-necked flask equipped with a thermometer, a stirrer and a constant-pressure dropping funnel. Stir and react for 30 - 40 min under the conditions of a temperature of 25 - 30 °C and a stirring rate of 300 - 400 r / min. Then, adjust the pH to 7 with sodium hydroxide solution. Then, add isopropanol and continue to stir and react for 20 - 30 min. Then, raise the temperature to 80 - 85 °C and gradually add the glycidyltrimethylammonium chloride solution dropwise while stirring, controlling the dropping rate at 1 - 2 drops / s. After the addition is complete, continue to stir and react for 2 - 3 h. After the reaction is completed, cool the reaction product to room temperature, then add it to absolute ethanol, then let it stand for precipitation, then vacuum filter. Place the filter cake in a vacuum drying oven and dry it for 2 - 3 h under the condition of a temperature of 50 - 55 °C to obtain modified chitosan;

[0011] Step s4: Add glycerol, (3-chloropropyl)triethoxysilane, anhydrous potassium carbonate, potassium iodide and anhydrous toluene into a three-necked flask equipped with a stirrer, a thermometer and a nitrogen inlet tube. Introduce nitrogen for protection and stir and react for 30 - 50 min under the conditions of a temperature of -5 - 0 °C and a stirring rate of 300 - 400 r / min. Then, raise the temperature to 80 - 85 °C and continue to stir and react for 20 - 25 h. After the reaction is completed, cool the reaction product to room temperature, then vacuum filter, rotate and evaporate the filtrate to remove the solvent, and then place it in a vacuum drying oven and dry it for 2 - 3 h under the condition of a temperature of 50 - 55 °C to obtain multi-group siloxane;

[0012] Step s5: Add polylactic acid, doped zinc oxide, modified chitosan, and N,N-dimethylformamide into a three-necked flask equipped with a thermometer, a stirrer, and a constant-pressure dropping funnel. Stir and react for 30 - 40 min under the conditions of a temperature of 25 - 30°C and a stirring rate of 300 - 400 r / min. Then, raise the temperature to 80 - 85°C and continue stirring and reacting for 2 - 3 h. After that, gradually add the multi-group siloxane solution drop by drop while stirring, control the dropping rate at 1 - 2 drops / s. After the dropping is completed, continue stirring and reacting for 2 - 3 h. After the reaction ends, cool the reaction product to room temperature, and then place it in a vacuum drying oven and dry it for 4 - 5 h under the condition of a temperature of 50 - 55°C to obtain the antibacterial substrate.

[0013] As a further scheme of the present invention: The dosage ratio of the zinc acetate and deionized water in step s1 is 4.5 - 5.5 g:50 mL.

[0014] The mass fraction of the sodium hydroxide solution in step s1 is 20 - 25%.

[0015] As a further scheme of the present invention: The dosage ratio of the nano-zinc oxide, deionized water, and silver nitrate solution in step s2 is 5 g:100 - 120 mL:10 - 15 mL.

[0016] As a further scheme of the present invention: The mass fraction of the silver nitrate solution in step s2 is 5 - 9%, and the mass fraction of the sodium hydroxide solution is 20 - 25%.

[0017] As a further scheme of the present invention: The dosage ratio of the chitosan, acetic acid solution, isopropanol, and glycidyltrimethylammonium chloride solution in step s3 is 5 g:80 - 100 mL:30 - 50 mL:10 - 15 mL.

[0018] As a further scheme of the present invention: The mass fraction of the sodium hydroxide solution in step s3 is 20 - 25%, the mass fraction of the acetic acid solution is 1 - 2%, and the mass concentration of the glycidyltrimethylammonium chloride solution is 0.5 - 0.9 g / mL.

[0019] As a further scheme of the present invention: The dosage ratio of glycerol, (3-chloropropyl)triethoxysilane, anhydrous potassium carbonate, potassium iodide, and anhydrous toluene in step s4 is 10 mmol:30 mmol:35 - 40 mmol:0.2 - 0.6 g:100 - 120 mL.

[0020] As a further solution of the present invention: the dosage ratio of the polylactic acid, doped zinc oxide, modified chitosan, N, N-dimethylformamide and multi-group silicone solution in step s5 is 10 g: 0.05 - 0.15 g: 0.4 - 0.8 g: 100 - 120 mL: 10 - 12 mL.

[0021] As a further solution of the present invention: the polylactic acid in step s5 is 4032d polylactic acid, and the multi-group silicone solution is a mixture of multi-group silicone, deionized water and absolute ethanol in a mass ratio of 1 - 5 g: 85 - 95 mL: 10 - 15 mL.

[0022] As a further solution of the present invention: a preparation method of a bio-based antibacterial packaging material includes the following steps:

[0023] Step 1: Weigh 35 - 45 parts of antibacterial substrate, 7 - 14 parts of plasticizer, 5 - 11 parts of talcum powder, 2 - 6 parts of titanium dioxide, 1.5 - 5.5 parts of compatibilizer, 1 - 3 parts of antioxidant and 1 - 3 parts of ultraviolet absorber by weight, and set aside;

[0024] Step 2: Add the antibacterial substrate, plasticizer, talcum powder, titanium dioxide, compatibilizer, antioxidant and ultraviolet absorber into a mixer, stir and mix evenly to obtain a mixture;

[0025] Step 3: Melt-extrude the mixture through an extruder, then pelletize and cut into particles to obtain the bio-based antibacterial packaging material.

[0026] As a further solution of the present invention: the plasticizer is one of dioctyl phthalate, butyl benzyl phthalate, diisononyl phthalate.

[0027] As a further solution of the present invention: the compatibilizer is one of PP-g-ST, ABS-g-MAH, PE-g-MAH.

[0028] As a further solution of the present invention: the antioxidant is one of antioxidant 1024, antioxidant 1076 and antioxidant 1330.

[0029] As a further solution of the present invention: the ultraviolet absorber is one of ultraviolet absorber UV-P, ultraviolet absorber UV-O, ultraviolet absorber UV-9.

[0030] The beneficial effects of the present invention:

[0031] A bio-based antibacterial packaging material and its preparation method of the present invention. An antibacterial substrate, a plasticizer, talcum powder, titanium dioxide, a compatibilizer, an antioxidant, and an ultraviolet absorber are added to a mixer, and after stirring and mixing evenly, a mixture is obtained. Then, the mixture is melt-extruded through an extruder, and then pelletized and cut into particles to obtain the bio-based antibacterial packaging material. In this preparation method, polylactic acid is reaction-modified with doped zinc oxide, modified chitosan, and multi-group siloxane to form an antibacterial substrate, endowing the bio-based antibacterial packaging material with a strong antibacterial ability, effectively inhibiting the growth of bacteria and molds. Moreover, polylactic acid is a bio-based material and can be naturally degraded, reducing environmental pollution. The prepared packaging material has excellent antibacterial performance, mechanical properties, and biodegradability, and has broad application prospects in the fields of food, medicine, and medical devices, which is of great significance for promoting the green development and sustainable development of the packaging industry.

[0032] In the process of preparing the bio-based antibacterial packaging material, an antibacterial substrate is first prepared. First, nano-zinc oxide is prepared using zinc acetate as a raw material, and then silver ions are doped and loaded on the nano-zinc oxide using silver nitrate as a raw material to obtain doped zinc oxide. Then, chitosan reacts with glycidyltrimethylammonium chloride, and the amino and hydroxyl groups on chitosan react with the epoxy groups on glycidyltrimethylammonium chloride to introduce a large number of quaternary ammonium groups to obtain modified chitosan. Then, glycerol reacts with (3-chloropropyl)triethoxysilane, and the hydroxyl group on glycerol reacts with the chlorine atom on (3-chloropropyl)triethoxysilane to introduce a large number of siloxane groups to obtain multi-group siloxane. Finally, polylactic acid is modified with doped zinc oxide, modified chitosan, and multi-group siloxane. After hydrolysis, the silanol formed by the multi-group siloxane can be grafted onto the surface of the doped zinc oxide, and can also be grafted onto the modified chitosan and polylactic acid. At the same time, the hydroxyl group on the modified chitosan and the carboxyl group on the polylactic acid can also react, so that polylactic acid, doped zinc oxide, modified chitosan, and multi-group siloxane are connected in the form of chemical bonds to obtain the antibacterial substrate. The antibacterial substrate uses the composite of the PLA matrix, modified chitosan, and doped zinc oxide, which significantly improves the mechanical strength and toughness of the antibacterial substrate. At the same time, the synergistic effect of the quaternary ammonium groups on the modified chitosan and the zinc ions and silver ions in the doped zinc oxide endows the antibacterial substrate with a strong antibacterial ability, effectively inhibiting the growth of bacteria and molds, and can effectively extend the shelf life of the products in the package. Moreover, the addition of multi-group siloxane can make the doped zinc oxide better dispersed in polylactic acid, making the antibacterial substrate have good biocompatibility and degradability, being environmentally friendly, and being of great significance for promoting the green development and sustainable development of the packaging industry. Specific embodiments

[0033] Next, in combination with the embodiments of the present invention, the technical solutions in the embodiments of the present invention will be clearly and completely described. Obviously, the described embodiments are only a part of the embodiments of the present invention, rather than all the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those of ordinary skill in the art without creative efforts shall fall within the protection scope of the present invention.

[0034] Example 1:

[0035] This example is a preparation method of a bio-based antibacterial packaging material, which includes the following steps:

[0036] Step S1: Add 4.5 g of zinc acetate and 50 mL of deionized water into a three-necked flask equipped with a thermometer and a stirrer, stir and react for 10 min under the conditions of a temperature of 25°C and a stirring rate of 300 r / min. Then, adjust the pH to 10 with a 20% sodium hydroxide solution, and then continue to stir and react for 30 min under the condition of raising the temperature to 50°C. Then, continue to stir and react for 10 h under the condition of raising the temperature to 160°C. After the reaction is completed, cool the reaction product to room temperature, and then centrifuge. Wash the precipitate with distilled water and absolute ethanol twice in sequence, and then place it in a vacuum drying oven and dry it for 2 h under the condition of a temperature of 60°C to obtain nano-zinc oxide;

[0037] Step S2: Add 5 g of nano-zinc oxide and 100 mL of deionized water into a three-necked flask equipped with a thermometer, a stirrer and a constant-pressure dropping funnel, stir and react for 10 min under the conditions of a temperature of 25°C and a stirring rate of 300 r / min. Then, while stirring, gradually add 10 mL of a 5% silver nitrate solution drop by drop, control the dropping rate to be 1 drop / s. After the dropping is completed, continue to stir and react for 1 h. Then, adjust the pH to 8 with a 20% sodium hydroxide solution, and then continue to stir and react for 4 h under the condition of raising the temperature to 80°C. After the reaction is completed, cool the reaction product to room temperature, and then centrifuge. Wash the precipitate with distilled water and absolute ethanol twice in sequence, and then place it in a vacuum drying oven and dry it for 2 h under the condition of a temperature of 60°C to obtain doped zinc oxide;

[0038] Step S3: Add 5 g of chitosan and 80 mL of 1% acetic acid solution into a three-necked flask equipped with a thermometer, a stirrer, and a constant-pressure dropping funnel. Stir and react for 30 min at a temperature of 25 °C and a stirring rate of 300 r / min. Then adjust the pH to 7 with 20% sodium hydroxide solution. After that, add 30 mL of isopropanol and continue to stir and react for 20 min. Then raise the temperature to 80 °C and gradually add 10 mL of glycidyltrimethylammonium chloride solution with a mass concentration of 0.5 g / mL drop by drop while stirring, controlling the dropping rate at 1 drop / s. After the dropping is completed, continue to stir and react for 2 h. After the reaction is completed, cool the reaction product to room temperature, then add it to anhydrous ethanol, then let it stand for precipitation, and then perform vacuum filtration. Place the filter cake in a vacuum drying oven and dry it at a temperature of 50 °C for 2 h to obtain modified chitosan;

[0039] Step S4: Add 10 mmol of glycerol, 30 mmol of (3-chloropropyl)triethoxysilane, 35 mmol of anhydrous potassium carbonate, 0.2 g of potassium iodide, and 100 mL of anhydrous toluene into a three-necked flask equipped with a stirrer, a thermometer, and a nitrogen inlet tube. Introduce nitrogen for protection and stir and react for 30 min at a temperature of -5 °C and a stirring rate of 300 r / min. Then raise the temperature to 80 °C and continue to stir and react for 20 h. After the reaction is completed, cool the reaction product to room temperature, then perform vacuum filtration, rotary evaporate the filtrate to remove the solvent, and then place it in a vacuum drying oven and dry it at a temperature of 50 °C for 2 h to obtain multi-group siloxane;

[0040] Step S5: Add 10 g of polylactic acid 4032d, 0.05 g of doped zinc oxide, 0.4 g of modified chitosan, and 100 mL of N,N-dimethylformamide into a three-necked flask equipped with a thermometer, a stirrer, and a constant-pressure dropping funnel. Stir and react for 30 min at a temperature of 25 °C and a stirring rate of 300 r / min. Then raise the temperature to 80 °C and continue to stir and react for 2 h. Then gradually add 10 mL of a multi-group siloxane solution prepared by mixing multi-group siloxane, deionized water, and anhydrous ethanol in a mass ratio of 1 g:85 mL:10 mL drop by drop while stirring, controlling the dropping rate at 1 drop / s. After the dropping is completed, continue to stir and react for 2 h. After the reaction is completed, cool the reaction product to room temperature, and then place it in a vacuum drying oven and dry it at a temperature of 50 °C for 4 h to obtain an antibacterial substrate;

[0041] Step S6: Weigh 35 parts of polylactic acid, 7 parts of plasticizer, 5 parts of talcum powder, 2 parts of titanium dioxide, 1.5 parts of compatibilizer, 1 part of antioxidant, and 1 part of ultraviolet absorber by weight, and set aside; the plasticizer is dioctyl phthalate; the compatibilizer is PP-g-ST; the antioxidant is antioxidant 1024; the ultraviolet absorber is ultraviolet absorber UV-P;

[0042] Step S7: Add the antibacterial substrate, plasticizer, talcum powder, titanium dioxide, compatibilizer, antioxidant, and ultraviolet absorber into a mixer, and stir and mix evenly to obtain a mixture;

[0043] Step S8: Melt and extrude the mixture through an extruder, and then pelletize and cut the pellets to obtain the bio-based antibacterial packaging material.

[0044] Example 2:

[0045] This example is a preparation method of a bio-based antibacterial packaging material, including the following steps:

[0046] Step S1: Add 5 g of zinc acetate and 50 mL of deionized water into a three-necked flask equipped with a thermometer and a stirrer, stir and react for 12 min at a temperature of 28 °C and a stirring rate of 350 r / min, then adjust the pH to 10.5 with a 22% sodium hydroxide solution, and then continue to stir and react for 35 min at a temperature of 52 °C, and then continue to stir and react for 11 h at a temperature of 165 °C. After the reaction is completed, cool the reaction product to room temperature, then centrifuge, wash the precipitate with distilled water and absolute ethanol twice each, and then place it in a vacuum drying oven and dry it at a temperature of 62 °C for 2.5 h to obtain nano-zinc oxide;

[0047] Step S2: Add 5 g of nano-zinc oxide and 110 mL of deionized water into a three-necked flask equipped with a thermometer, a stirrer and a constant pressure dropping funnel, stir and react for 12 min at a temperature of 28 °C and a stirring rate of 350 r / min, then dropwise add 12 mL of 7% silver nitrate solution drop by drop while stirring, control the dropping rate at 1 drop / s, continue to stir and react for 1.2 h after dropping, then adjust the pH to 8.5 with a 22% sodium hydroxide solution, and then continue to stir and react for 4.5 h at a temperature of 82 °C. After the reaction is completed, cool the reaction product to room temperature, then centrifuge, wash the precipitate with distilled water and absolute ethanol twice each, and then place it in a vacuum drying oven and dry it at a temperature of 62 °C for 2.5 h to obtain doped zinc oxide;

[0048] Step S3: Add 5 g of chitosan and 90 mL of acetic acid solution with a mass fraction of 1.5% into a three-necked flask equipped with a thermometer, a stirrer, and a constant-pressure dropping funnel. Stir and react for 35 min under the conditions of a temperature of 28 °C and a stirring rate of 350 r / min. Then adjust the pH to 7 with a sodium hydroxide solution with a mass fraction of 22%. Then add 40 mL of isopropanol and continue to stir and react for 25 min. Then raise the temperature to 82 °C and gradually add 12 mL of glycidyltrimethylammonium chloride solution with a mass concentration of 0.7 g / mL drop by drop while stirring, controlling the dropping rate at 1 drop / s. After the dropping is completed, continue to stir and react for 2.5 h. After the reaction is completed, cool the reaction product to room temperature, then add it to absolute ethanol, then let it stand for precipitation, then carry out vacuum filtration. Place the filter cake in a vacuum drying oven and dry it at a temperature of 52 °C for 2.5 h to obtain modified chitosan;

[0049] Step S4: Add 10 mmol of glycerol, 30 mmol of (3-chloropropyl)triethoxysilane, 38 mmol of anhydrous potassium carbonate, 0.4 g of potassium iodide, and 110 mL of anhydrous toluene into a three-necked flask equipped with a stirrer, a thermometer, and a nitrogen inlet tube. Introduce nitrogen for protection and stir and react for 40 min under the conditions of a temperature of -3 °C and a stirring rate of 350 r / min. Then raise the temperature to 82 °C and continue to stir and react for 22 h. After the reaction is completed, cool the reaction product to room temperature, then carry out vacuum filtration. Rotate and evaporate the filtrate to remove the solvent, then place it in a vacuum drying oven and dry it at a temperature of 52 °C for 2.5 h to obtain multi-group silicone;

[0050] Step S5: Add 10 g of polylactic acid 4032d, 0.1 g of doped zinc oxide, 0.6 g of modified chitosan, and 110 mL of N,N-dimethylformamide into a three-necked flask equipped with a thermometer, a stirrer, and a constant-pressure dropping funnel. Stir and react for 35 min under the conditions of a temperature of 28 °C and a stirring rate of 350 r / min. Then raise the temperature to 82 °C and continue to stir and react for 2.5 h. Then gradually add 11 mL of a multi-group silicone solution prepared by mixing multi-group silicone, deionized water, and absolute ethanol in a mass ratio of 3 g:90 mL:12 mL drop by drop while stirring, controlling the dropping rate at 1 drop / s. After the dropping is completed, continue to stir and react for 2.5 h. After the reaction is completed, cool the reaction product to room temperature, then place it in a vacuum drying oven and dry it at a temperature of 52 °C for 4.5 h to obtain an antibacterial substrate;

[0051] Step S6: Weigh 40 parts of antibacterial substrate, 10 parts of plasticizer, 8 parts of talcum powder, 4 parts of titanium dioxide, 3.5 parts of compatibilizer, 2 parts of antioxidant and 2 parts of ultraviolet absorber by weight for standby; the plasticizer is butyl benzyl phthalate; the compatibilizer is ABS-g-MAH; the antioxidant is antioxidant 1076; the ultraviolet absorber is ultraviolet absorber UV-O;

[0052] Step S7: Add the antibacterial substrate, plasticizer, talcum powder, titanium dioxide, compatibilizer, antioxidant and ultraviolet absorber into a mixer, and stir and mix evenly to obtain a mixture;

[0053] Step S8: Melt-extrude the mixture through an extruder, and then pelletize and cut the pellets to obtain the bio-based antibacterial packaging material.

[0054] Example 3:

[0055] This example is a preparation method of a bio-based antibacterial packaging material, including the following steps:

[0056] Step S1: Add 5.5 g of zinc acetate and 50 mL of deionized water into a three-necked flask equipped with a thermometer and a stirrer, stir and react for 15 min at a temperature of 30 °C and a stirring rate of 400 r / min, then adjust the pH to 11 with a 25% sodium hydroxide solution, and then continue to stir and react for 40 min at a temperature of 55 °C, and then continue to stir and react for 12 h at a temperature of 170 °C. After the reaction is completed, cool the reaction product to room temperature, then centrifuge, wash the precipitate with distilled water and absolute ethanol 3 times each, and then place it in a vacuum drying oven and dry it for 3 h at a temperature of 65 °C to obtain nano-zinc oxide;

[0057] Step S2: Add 5 g of nano-zinc oxide and 120 mL of deionized water into a three-necked flask equipped with a thermometer, a stirrer and a constant-pressure dropping funnel, stir and react for 15 min at a temperature of 30 °C and a stirring rate of 400 r / min, then gradually add 15 mL of 9% silver nitrate solution dropwise while stirring, control the dropping rate at 2 drops / s, continue to stir and react for 1.5 h after dropping, then adjust the pH to 9 with a 25% sodium hydroxide solution, and then continue to stir and react for 5 h at a temperature of 85 °C. After the reaction is completed, cool the reaction product to room temperature, then centrifuge, wash the precipitate with distilled water and absolute ethanol 3 times each, and then place it in a vacuum drying oven and dry it for 3 h at a temperature of 65 °C to obtain doped zinc oxide;

[0058] Step S3: Add 5 g of chitosan and 100 mL of 2% acetic acid solution by mass to a three-necked flask equipped with a thermometer, a stirrer, and a constant-pressure dropping funnel. Stir and react for 40 min at a temperature of 30 °C and a stirring rate of 400 r / min. Then adjust the pH to 7 with 25% sodium hydroxide solution by mass. After that, add 50 mL of isopropanol and continue to stir and react for 30 min. Then, while stirring, gradually add 15 mL of glycidyltrimethylammonium chloride solution with a mass concentration of 0.9 g / mL dropwise at a temperature of 85 °C, controlling the dropping rate at 2 drops / s. After the addition is complete, continue to stir and react for 3 h. After the reaction is completed, cool the reaction product to room temperature, then add it to absolute ethanol, then let it stand for precipitation, and then perform vacuum filtration. Place the filter cake in a vacuum drying oven and dry it at a temperature of 55 °C for 3 h to obtain modified chitosan;

[0059] Step S4: Add 10 mmol of glycerol, 30 mmol of (3-chloropropyl)triethoxysilane, 40 mmol of anhydrous potassium carbonate, 0.6 g of potassium iodide, and 120 mL of anhydrous toluene to a three-necked flask equipped with a stirrer, a thermometer, and a nitrogen inlet tube. Introduce nitrogen for protection and stir and react for 50 min at a temperature of 0 °C and a stirring rate of 400 r / min. Then continue to stir and react for 25 h at a temperature of 85 °C. After the reaction is completed, cool the reaction product to room temperature, then perform vacuum filtration, rotary evaporate the filtrate to remove the solvent, and then place it in a vacuum drying oven and dry it at a temperature of 55 °C for 3 h to obtain multi-group siloxane;

[0060] Step S5: Add 10 g of polylactic acid 4032d, 0.15 g of doped zinc oxide, 0.8 g of modified chitosan, and 120 mL of N,N-dimethylformamide to a three-necked flask equipped with a thermometer, a stirrer, and a constant-pressure dropping funnel. Stir and react for 40 min at a temperature of 30 °C and a stirring rate of 400 r / min. Then continue to stir and react for 3 h at a temperature of 85 °C. Then, while stirring, gradually add 12 mL of a multi-group siloxane solution prepared by mixing multi-group siloxane, deionized water, and absolute ethanol in a mass ratio of 5 g:95 mL:15 mL dropwise, controlling the dropping rate at 2 drops / s. After the addition is complete, continue to stir and react for 3 h. After the reaction is completed, cool the reaction product to room temperature, and then place it in a vacuum drying oven and dry it at a temperature of 55 °C for 5 h to obtain an antibacterial substrate;

[0061] Step S6: Weigh 45 parts of antibacterial substrate, 14 parts of plasticizer, 11 parts of talcum powder, 6 parts of titanium dioxide, 5.5 parts of compatibilizer, 3 parts of antioxidant, and 3 parts of ultraviolet absorber for standby; the plasticizer is diisononyl phthalate; the compatibilizer is PE-g-MAH; the antioxidant is antioxidant 1330; the ultraviolet absorber is ultraviolet absorber UV-9;

[0062] Step S7: Add the antibacterial substrate, plasticizer, talcum powder, titanium dioxide, compatibilizer, antioxidant, and ultraviolet absorber into a mixer, and stir and mix evenly to obtain a mixture;

[0063] Step S8: Melt and extrude the mixture through an extruder, and then granulate and cut it to obtain a bio-based antibacterial packaging material.

[0064] Comparative Example 1:

[0065] This comparative example is a preparation method of a bio-based antibacterial packaging material, including the following steps:

[0066] Step S1: Weigh 35 parts of polylactic acid, 7 parts of plasticizer, 5 parts of talcum powder, 2 parts of titanium dioxide, 1.5 parts of compatibilizer, 1 part of antioxidant, and 1 part of ultraviolet absorber for standby; the plasticizer is dioctyl phthalate; the compatibilizer is PP-g-ST; the antioxidant is antioxidant 1024; the ultraviolet absorber is ultraviolet absorber UV-P;

[0067] Step S2: Add the antibacterial substrate, plasticizer, talcum powder, titanium dioxide, compatibilizer, antioxidant, and ultraviolet absorber into a mixer, and stir and mix evenly to obtain a mixture;

[0068] Step S3: Melt and extrude the mixture through an extruder, and then granulate and cut it to obtain a bio-based antibacterial packaging material.

[0069] Comparative Example 2:

[0070] This comparative example is a preparation method of a bio-based antibacterial packaging material, including the following steps:

[0071] Step S1: Add 5.5 g of zinc acetate and 50 mL of deionized water into a three-necked flask equipped with a thermometer and a stirrer. Stir and react for 15 min under the conditions of a temperature of 30 °C and a stirring rate of 400 r / min. Then adjust the pH to 11 with a 25% sodium hydroxide solution. After that, continue to stir and react for 40 min under the condition of heating up to 55 °C, and then continue to stir and react for 12 h under the condition of heating up to 170 °C. After the reaction is completed, cool the reaction product to room temperature, then centrifuge, wash the precipitate with distilled water and absolute ethanol three times in sequence, and then place it in a vacuum drying oven and dry for 3 h under the condition of a temperature of 65 °C to obtain nano-zinc oxide;

[0072] Step S2: Add 5 g of nano-zinc oxide and 120 mL of deionized water into a three-necked flask equipped with a thermometer, a stirrer and a constant pressure dropping funnel. Stir and react for 15 min under the conditions of a temperature of 30 °C and a stirring rate of 400 r / min. Then, while stirring, gradually add 15 mL of a 9% silver nitrate solution drop by drop, control the dropping rate at 2 drops / s. After the dropping is completed, continue to stir and react for 1.5 h. Then adjust the pH to 9 with a 25% sodium hydroxide solution. After that, continue to stir and react for 5 h under the condition of heating up to 85 °C. After the reaction is completed, cool the reaction product to room temperature, then centrifuge, wash the precipitate with distilled water and absolute ethanol three times in sequence, and then place it in a vacuum drying oven and dry for 3 h under the condition of a temperature of 65 °C to obtain doped zinc oxide;

[0073] Step S3: Add 5 g of chitosan and 100 mL of a 2% acetic acid solution into a three-necked flask equipped with a thermometer, a stirrer and a constant pressure dropping funnel. Stir and react for 40 min under the conditions of a temperature of 30 °C and a stirring rate of 400 r / min. Then adjust the pH to 7 with a 25% sodium hydroxide solution. After that, add 50 mL of isopropanol and continue to stir and react for 30 min. Then, while stirring, gradually add 15 mL of a trimethylammonium glycidyl chloride solution with a mass concentration of 0.9 g / mL drop by drop under the condition of heating up to 85 °C, control the dropping rate at 2 drops / s. After the dropping is completed, continue to stir and react for 3 h. After the reaction is completed, cool the reaction product to room temperature, then add it to absolute ethanol, then let it stand for precipitation, and then vacuum filter. Place the filter cake in a vacuum drying oven and dry for 3 h under the condition of a temperature of 55 °C to obtain modified chitosan;

[0074] Step S4: Add 10 g of polylactic acid 4032d, 0.15 g of doped zinc oxide, 0.8 g of modified chitosan, and 120 mL of N,N-dimethylformamide into a three-necked flask equipped with a thermometer, a stirrer, and a constant-pressure dropping funnel. Stir and react for 40 min under the conditions of a temperature of 30 °C and a stirring rate of 400 r / min. Then, continue to stir and react for 3 h under the condition of raising the temperature to 85 °C. After the reaction is completed, cool the reaction product to room temperature, and then place it in a vacuum drying oven and dry it for 5 h under the condition of a temperature of 55 °C to obtain an antibacterial substrate;

[0075] Step S5: Weigh 45 parts of the antibacterial substrate, 14 parts of a plasticizer, 11 parts of talcum powder, 6 parts of titanium dioxide, 5.5 parts of a compatibilizer, 3 parts of an antioxidant, and 3 parts of an ultraviolet absorber by weight for standby; the plasticizer is diisononyl phthalate; the compatibilizer is PE-g-MAH; the antioxidant is antioxidant 1330; the ultraviolet absorber is ultraviolet absorber UV-9;

[0076] Step S6: Add the antibacterial substrate, the plasticizer, the talcum powder, the titanium dioxide, the compatibilizer, the antioxidant, and the ultraviolet absorber into a mixer, and stir and mix evenly to obtain a mixed material;

[0077] Step S7: Melt and extrude the mixed material through an extruder, and then pelletize and cut it to obtain a bio-based antibacterial packaging material.

[0078] Comparative Example 3:

[0079] This comparative example is a preparation method of a bio-based antibacterial packaging material, including the following steps:

[0080] Step S1: Add 5.5 g of zinc acetate and 50 mL of deionized water into a three-necked flask equipped with a thermometer and a stirrer. Stir and react for 15 min under the conditions of a temperature of 30 °C and a stirring rate of 400 r / min. Then, adjust the pH to 11 with a 25% sodium hydroxide solution by mass fraction, and then continue to stir and react for 40 min under the condition of raising the temperature to 55 °C. Then, continue to stir and react for 12 h under the condition of raising the temperature to 170 °C. After the reaction is completed, cool the reaction product to room temperature, and then centrifuge it. Wash the precipitate with distilled water and absolute ethanol three times respectively, and then place it in a vacuum drying oven and dry it for 3 h under the condition of a temperature of 65 °C to obtain nano-zinc oxide;

[0081] Step S2: Add 5 g of nano-zinc oxide and 120 mL of deionized water into a three-necked flask equipped with a thermometer, a stirrer, and a constant-pressure dropping funnel. Stir and react for 15 min at a temperature of 30 °C and a stirring rate of 400 r / min. Then, while stirring, gradually add 15 mL of a 9% silver nitrate solution dropwise, controlling the dropping rate at 2 drops / s. After the addition is complete, continue stirring and reacting for 1.5 h. Then, adjust the pH to 9 with a 25% sodium hydroxide solution. Then, raise the temperature to 85 °C and continue stirring and reacting for 5 h. After the reaction is completed, cool the reaction product to room temperature, then centrifuge. Wash the precipitate with distilled water and absolute ethanol three times each. Then, place it in a vacuum drying oven and dry it at a temperature of 65 °C for 3 h to obtain doped zinc oxide;

[0082] Step S3: Add 10 mmol of glycerol, 30 mmol of (3-chloropropyl)triethoxysilane, 40 mmol of anhydrous potassium carbonate, 0.6 g of potassium iodide, and 120 mL of anhydrous toluene into a three-necked flask equipped with a stirrer, a thermometer, and a nitrogen inlet tube. Introduce nitrogen for protection and stir and react for 50 min at a temperature of 0 °C and a stirring rate of 400 r / min. Then, raise the temperature to 85 °C and continue stirring and reacting for 25 h. After the reaction is completed, cool the reaction product to room temperature, then perform vacuum filtration. Rotate and evaporate the filtrate to remove the solvent. Then, place it in a vacuum drying oven and dry it at a temperature of 55 °C for 3 h to obtain multi-group siloxane;

[0083] Step S4: Add 10 g of polylactic acid 4032d, 0.15 g of doped zinc oxide, and 120 mL of N,N-dimethylformamide into a three-necked flask equipped with a thermometer, a stirrer, and a constant-pressure dropping funnel. Stir and react for 40 min at a temperature of 30 °C and a stirring rate of 400 r / min. Then, raise the temperature to 85 °C and continue stirring and reacting for 3 h. Then, while stirring, gradually add 12 mL of a multi-group siloxane solution prepared by mixing multi-group siloxane, deionized water, and absolute ethanol in a mass ratio of 5 g:95 mL:15 mL dropwise, controlling the dropping rate at 2 drops / s. After the addition is complete, continue stirring and reacting for 3 h. After the reaction is completed, cool the reaction product to room temperature, then place it in a vacuum drying oven and dry it at a temperature of 55 °C for 5 h to obtain an antibacterial substrate;

[0084] Step S5: Weigh 45 parts of antibacterial substrate, 14 parts of plasticizer, 11 parts of talc powder, 6 parts of titanium dioxide, 5.5 parts of compatibilizer, 3 parts of antioxidant, and 3 parts of ultraviolet absorber by weight for standby; the plasticizer is diisononyl phthalate; the compatibilizer is PE-g-MAH; the antioxidant is antioxidant 1330; the ultraviolet absorber is ultraviolet absorber UV-9;

[0085] Step S6: Add the antibacterial substrate, plasticizer, talcum powder, titanium dioxide, compatibilizer, antioxidant, and ultraviolet absorber into a mixer, and obtain a mixed material after stirring and mixing evenly.

[0086] Step S7: Melt and extrude the mixed material through an extruder, then pelletize and cut it to obtain the bio-based antibacterial packaging material.

[0087] Comparative Example 4:

[0088] This comparative example is a preparation method of a bio-based antibacterial packaging material, including the following steps:

[0089] Step S1: Add 5 g of chitosan and 100 mL of acetic acid solution with a mass fraction of 2% into a three-necked flask equipped with a thermometer, a stirrer, and a constant-pressure dropping funnel. Stir and react for 40 min under the conditions of a temperature of 30 °C and a stirring rate of 400 r / min. Then adjust the pH to 7 with a sodium hydroxide solution with a mass fraction of 25%. Then add 50 mL of isopropanol and continue to stir and react for 30 min. Then raise the temperature to 85 °C and gradually add 15 mL of glycidyltrimethylammonium chloride solution with a mass concentration of 0.9 g / mL drop by drop while stirring, controlling the dropping rate at 2 drops / s. After the dropping is completed, continue to stir and react for 3 h. After the reaction is completed, cool the reaction product to room temperature, then add it to absolute ethanol, then let it stand for precipitation, then carry out vacuum filtration. Place the filter cake in a vacuum drying oven and dry it at a temperature of 55 °C for 3 h to obtain modified chitosan.

[0090] Step S2: Add 10 mmol of glycerol, 30 mmol of (3-chloropropyl)triethoxysilane, 40 mmol of anhydrous potassium carbonate, 0.6 g of potassium iodide, and 120 mL of anhydrous toluene into a three-necked flask equipped with a stirrer, a thermometer, and a nitrogen inlet tube. Introduce nitrogen for protection and stir and react for 50 min under the conditions of a temperature of 0 °C and a stirring rate of 400 r / min. Then raise the temperature to 85 °C and continue to stir and react for 25 h. After the reaction is completed, cool the reaction product to room temperature, then carry out vacuum filtration. Rotate and evaporate the filtrate to remove the solvent, then place it in a vacuum drying oven and dry it at a temperature of 55 °C for 3 h to obtain multi-group silicone.

[0091] Step S3: Add 10 g of polylactic acid 4032d, 0.8 g of modified chitosan, and 120 mL of N,N-dimethylformamide into a three-necked flask equipped with a thermometer, a stirrer, and a constant-pressure dropping funnel. Stir and react for 40 min under the conditions of a temperature of 30 °C and a stirring rate of 400 r / min. Then, raise the temperature to 85 °C and continue to stir and react for 3 h. After that, while stirring, gradually add dropwise a multi-group silicone solution prepared by mixing 12 mL of multi-group silicone, deionized water, and absolute ethanol in a mass ratio of 5 g:95 mL:15 mL. Control the dropping rate at 2 drops / s. After the dropping is completed, continue to stir and react for 3 h. After the reaction is completed, cool the reaction product to room temperature, and then place it in a vacuum drying oven and dry it at a temperature of 55 °C for 5 h to obtain an antibacterial substrate;

[0092] Step S4: Weigh 45 parts of the antibacterial substrate, 14 parts of the plasticizer, 11 parts of talc powder, 6 parts of titanium dioxide, 5.5 parts of the compatibilizer, 3 parts of the antioxidant, and 3 parts of the ultraviolet absorber by weight and set aside; the plasticizer is diisononyl phthalate; the compatibilizer is PE-g-MAH; the antioxidant is antioxidant 1330; the ultraviolet absorber is ultraviolet absorber UV-9;

[0093] Step S5: Add the antibacterial substrate, the plasticizer, the talc powder, the titanium dioxide, the compatibilizer, the antioxidant, and the ultraviolet absorber into a mixer, and stir and mix evenly to obtain a mixed material;

[0094] Step S6: Melt and extrude the mixed material through an extruder, and then pelletize and cut it to obtain a bio-based antibacterial packaging material.

[0095] Test the properties of the bio-based antibacterial packaging materials of Examples 1-3 and Comparative Examples 1-4. The test results are as follows:

[0096]

[0097] Referring to the data in the above table, according to the comparison between Examples 1-3 and Comparative Examples 1-4, it can be known that adding doped zinc oxide and modified chitosan can greatly improve the antibacterial performance of the bio-based antibacterial packaging material, and adding multi-group silicone can further improve its antibacterial performance, making the prepared bio-based antibacterial packaging material have excellent antibacterial performance.

[0098] In the description of this specification, the descriptions referring to terms such as "one embodiment", "example", "specific example", etc. mean that the specific features, structures, materials or characteristics described in connection with the embodiment or example are included in at least one embodiment or example of the present invention. In this specification, the schematic representations of the above terms do not necessarily refer to the same embodiment or example. Moreover, the specific features, structures, materials or characteristics described can be combined in a suitable manner in any one or more embodiments or examples.

[0099] The above content is only an example and illustration of the present invention. Those skilled in the art of this technology can make various modifications or supplements to the described specific embodiments or use similar ways to substitute, as long as they do not deviate from the invention or exceed the scope defined by the claims of the present invention, they should all fall within the protection scope of the present invention.

Claims

1. A bio-based antibacterial packaging material, characterized in that: It includes the following components by weight: 35-45 parts of antibacterial base material, 7-14 parts of plasticizer, 5-11 parts of talc, 2-6 parts of titanium dioxide, 1.5-5.5 parts of compatibilizer, 1-3 parts of antioxidant and 1-3 parts of ultraviolet absorber; Wherein, the antibacterial substrate is prepared by the following steps: Step s1: stirring zinc acetate and deionized water for reaction, and then adjusting the pH with sodium hydroxide solution. After the reaction is completed, the reaction product is cooled, centrifuged, and the precipitate is washed and dried to obtain nano zinc oxide; Step s2: stirring the nano zinc oxide and deionized water for reaction, then adding the silver nitrate solution dropwise while stirring, continuing the stirring reaction after the addition is complete, then adjusting the pH with a sodium hydroxide solution, cooling the reaction product after the reaction is complete, then centrifuging, washing and drying the precipitate to obtain doped zinc oxide; Step s3: stirring the chitosan and acetic acid solution to react, then adjusting the pH with a sodium hydroxide solution, then adding isopropanol and continuing to stir the reaction, then adding the glycidyl trimethylammonium chloride solution dropwise while stirring, and continuing to stir the reaction after the dropwise addition is completed. After the reaction is completed, the reaction product is cooled, then added to anhydrous ethanol, then allowed to stand and precipitate, then vacuum filtered, and the filter cake is dried to obtain modified chitosan; Step s4: stirring glycerol, (3-chloropropyl)triethoxysilane, anhydrous potassium carbonate, potassium iodide and anhydrous toluene for reaction, cooling the reaction product after the reaction is completed, then vacuum filtering, rotary evaporating the filtrate, and then drying to obtain multi-group siloxane; Step s5: Stirring polylactic acid, doped zinc oxide, modified chitosan and N,N-dimethylformamide for reaction, then adding the multi-group siloxane solution dropwise while stirring, and continuing to stir the reaction after the addition is completed. After the reaction is completed, the reaction product is cooled and then dried to obtain an antibacterial substrate.

2. The bio-based antibacterial packaging material according to claim 1, characterized in that: The dosage ratio of the zinc acetate and deionized water in step s1 is 4.5-5.5 g:50 mL; the mass fraction of the sodium hydroxide solution in step s1 is 20-25%.

3. The bio-based antibacterial packaging material according to claim 1, characterized in that: The dosage ratio of the nano zinc oxide, deionized water and silver nitrate solution in step s2 is 5g:100-120mL:10-15mL; the mass fraction of the silver nitrate solution in step s2 is 5-9%, and the mass fraction of the sodium hydroxide solution is 20-25%.

4. The bio-based antibacterial packaging material according to claim 1, characterized in that: The amount ratio of the chitosan, acetic acid solution, isopropanol and glycidyl trimethylammonium chloride solution in step s3 is 5g:80-100mL:30-50mL:10-15mL; the mass fraction of the sodium hydroxide solution in step s3 is 20-25%, the mass fraction of the acetic acid solution is 1-2%, and the mass concentration of the glycidyl trimethylammonium chloride solution is 0.5-0.9g / mL.

5. The bio-based antibacterial packaging material according to claim 1, characterized in that: The usage ratio of the glycerol, (3-chloropropyl)triethoxysilane, anhydrous potassium carbonate, potassium iodide and anhydrous toluene in step s4 is 10mmol:30mmol:35-40mmol:0.2-0.6g:100-120mL.

6. The bio-based antibacterial packaging material according to claim 1, characterized in that: The amount ratio of the polylactic acid, doped zinc oxide, modified chitosan, N,N-dimethylformamide and multi-group siloxane solution in step s5 is 10g: 0.05-0.15g: 0.4-0.8g: 100-120mL: 10-12mL; the polylactic acid in step s5 is 4032d polylactic acid, and the multi-group siloxane solution is a mixture of multi-group siloxane, deionized water and anhydrous ethanol in a mass ratio of 1-5g: 85-95mL: 10-15mL.

7. A method for preparing a bio-based antimicrobial packaging material according to any one of claims 1 to 6, characterized in that: The following steps are involved: Step 1: Weigh 35-45 parts of antibacterial substrate, 7-14 parts of plasticizer, 5-11 parts of talcum powder, 2-6 parts of titanium dioxide, 1.5-5.5 parts of compatibilizer, 1-3 parts of antioxidant and 1-3 parts of ultraviolet absorber according to weight parts, and set aside; Step 2: adding the antibacterial substrate, plasticizer, talcum powder, titanium dioxide, compatibilizer, antioxidant and ultraviolet absorber into a mixer, stirring and mixing to obtain a mixture; Step 3: The mixed material is melt-extruded through an extruder, and then granulated and pelletized to obtain a bio-based antibacterial packaging material.

8. The method for preparing a bio-based antibacterial packaging material according to claim 7, characterized in that: The plasticizer is one of dioctyl phthalate, butyl benzyl phthalate and diisononyl phthalate; the compatibilizer is one of PP-g-ST, ABS-g-MAH and PE-g-MAH.

9. The method for preparing a bio-based antibacterial packaging material according to claim 7, characterized in that: The antioxidant is one of antioxidant 1024, antioxidant 1076 and antioxidant 1330; the ultraviolet absorber is one of ultraviolet absorber UV-P, ultraviolet absorber UV-O and ultraviolet absorber UV-9.

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