Degradable antibacterial plastic packaging bag and preparation method thereof

Abstract

The invention belongs to the technical field of plastics, and particularly relates to a degradable antibacterial plastic packaging bag and a preparation method thereof. The degradable antibacterial plastic packaging bag disclosed by the invention is prepared from the following raw materials in parts by weight: 70 to 90 parts of polycaprolactone; 20 to 40 parts of poly (butylene adipate-co-terephthalate); 1 to 5 parts of Cr and Cu co-modified ZIF-81; and 2-6 parts of a cerium oxide tannate material. According to the degradable antibacterial plastic packaging bag, ZIF-8 is co-modified through Cr and Cu, the antibacterial performance of the packaging bag is improved through synergistic interaction, the antibacterial performance of the packaging bag is further improved by adding a cerium oxide tannate material, and the prepared degradable antibacterial plastic packaging bag is excellent in mechanical property.

Description

Technical Field

[0001] The present invention belongs to the technical field of plastics. More specifically, it relates to a degradable antibacterial plastic packaging bag and a preparation method thereof. Background Art

[0002] Food is easily contaminated by microorganisms and spoils. Food packaging is an effective means to ensure food safety. Commercialized packaging such as polyethylene (PE), polyvinyl chloride (PVC), and polyvinylidene chloride (PVDC) has problems such as being difficult to degrade, poor antibacterial performance, and large environmental pollution. Therefore, the development of degradable antibacterial preservation materials has become a research hotspot in the field of food packaging.

[0003] Biodegradable materials can undergo chemical or physical changes under the action of natural microorganisms, decompose from polymers into small molecules, and ultimately decompose into carbon dioxide and water. Such materials do not put pressure on the environment during use, and using this type of plastic products is a powerful measure to solve white pollution. Commonly studied degradable polymer materials can generally be divided into two categories: natural polymer materials and synthetic polymer materials. Natural polymer materials include materials such as polysaccharides, proteins, and lipids. The development of synthetic biodegradable plastics is rapid, and related materials such as poly-β-hydroxybutyric acid (PHB), polybutylene adipate terephthalate (PBAT), and polybutylene succinate (PBS) are favored by people and are expected to replace traditional plastics.

[0004] The physical puncture mechanism of MOF and MOF-based composite materials refers to that through non-covalent interactions such as van der Waals forces and electrostatic interactions, the sharp edges in the nanostructure of MOF and MOF-based composite materials come into contact with the bacterial cell membrane, causing the cell membrane to rupture and resulting in the death of bacteria.

[0005] Metal ions are coordinated with tannic acid (TA), and a variety of different metal polyphenol-based nano antibacterial materials are prepared by a one-step blending method. Its combination of polyphenols on the surface of tannic acid and the coordination of metal ions achieves co-antibacterial and has excellent antibacterial performance.

[0006] CN119307078A discloses a high-sealing packaging bag and its preparation process, belonging to the technical field of packaging materials. The packaging bag comprises the following raw materials: polylactic acid, polycaprolactone, nano-silver filler composite antibacterial agent and epoxy-based compatibilizer; the nano-silver filler composite antibacterial agent is nano-silver loaded after a hybrid modified coating is deposited on the surface of nano two-dimensional filler; the hybrid modified coating includes polydopamine and hyperbranched polyethyleneimine. Using polylactic acid and polycaprolactone as the main base materials, the packaging bag is given good mechanical properties by the high mechanical strength of polylactic acid and the excellent flexibility of polycaprolactone; a nano-silver filler composite antibacterial agent and an epoxy-based compatibilizer are also added. Among them, the nano-silver filler composite antibacterial agent uses nano two-dimensional filler as the raw material. The nano two-dimensional filler has a high aspect ratio and can block the permeation of gas molecules. Combining with the epoxy-based compatibilizer to improve the dispersion performance, further improving the barrier performance and mechanical properties of the packaging bag.

[0007] CN119019826A discloses a biodegradable milk tea packaging bag and its preparation method; a biodegradable milk tea packaging bag comprises the following raw materials in parts by weight: 40-60 parts of poly(butylene adipate-co-terephthalate), 20-30 parts of polylactic acid, 5-15 parts of modified starch, 5-8 parts of diatom shell, 5-8 parts of inorganic filler, 1-3 parts of anti-hydrolytic agent, 0.5-1 part of chain extender, 1-3 parts of lubricant, 1-3 parts of toughening and plasticizing agent, 0.4-0.8 parts of hydroxy silicone oil, 0.5-1.5 parts of antibacterial agent; the packaging bag prepared in this application improves the tensile strength and thermal stability of the packaging bag by compounding poly(butylene adipate-co-terephthalate) and polylactic acid, and reduces the deformation and damage of the packaging bag.

[0008] In documents such as CN118755242A, CN118620367A, and CN118496634A, it is recorded that antibacterial components are added to the packaging bag to endow the packaging bag with antibacterial properties. Based on the above content, the present invention provides a new biodegradable antibacterial plastic packaging bag, which has excellent antibacterial properties and mechanical properties. Summary of the Invention

[0009] The technical problem to be solved by the present invention is to overcome the defects and deficiencies in the prior art and provide a biodegradable antibacterial plastic packaging bag and its preparation method. The biodegradable antibacterial plastic packaging bag of the present invention, by weight, comprises the following raw materials: 70-90 parts of polycaprolactone; 20-40 parts of poly(butylene adipate-co-terephthalate); 1-5 parts of Cr and Cu co-modified ZIF-8; 2-6 parts of cerium oxidized tannate material. The present invention co-modifies ZIF-8 with Cr and Cu, synergistically enhancing the antibacterial performance of the packaging bag. By adding cerium oxidized tannate material, the antibacterial performance of the packaging bag is further improved, and the biodegradable antibacterial plastic packaging bag prepared by the present invention has excellent mechanical properties.

[0010] The object of the present invention is to provide a degradable antibacterial plastic packaging bag.

[0011] Another object of the present invention is to provide a preparation method of a degradable antibacterial plastic packaging bag.

[0012] The above objects of the present invention are achieved by the following technical solutions:

[0013] A degradable antibacterial plastic packaging bag, by weight, comprises the following raw materials: 70-90 parts of polycaprolactone; 20-40 parts of poly(butylene adipate-co-terephthalate); 1-5 parts of Cr and Cu co-modified ZIF-8; 2-6 parts of cerium oxidized tannate material.

[0014] In the present invention, in a preferred embodiment, the preparation method of the Cr and Cu co-modified ZIF-8 comprises the following steps:

[0015] Chromium salt, copper salt, zinc salt and 2-methylimidazole are ultrasonically dispersed in ethanol, stirred, and then hydrothermally treated, filtered, washed, and vacuum dried to obtain Cr and Cu co-modified ZIF-8.

[0016] Preferably, the chromium salt is one of chromium nitrate, chromium acetate, and chromium chloride; the copper salt is one of copper nitrate, copper acetate, and copper chloride; the zinc salt is one of zinc nitrate, zinc acetate, and zinc chloride; the molar ratio of the chromium salt, copper salt, zinc salt and 2-methylimidazole is 0.02-0.06:0.01-0.05:1.5:3-4.

[0017] Preferably, the stirring time is 20-40 min.

[0018] More preferably, the conditions of the hydrothermal treatment are hydrothermal treatment at 140-180 °C for 10-20 h; the vacuum drying is vacuum drying at 60-90 °C for 14-20 h.

[0019] In the present invention, in a more preferred embodiment, the preparation method of the cerium oxidized tannate material comprises the following steps:

[0020] Tannic acid and sodium periodate are ultrasonically dispersed in deionized water and stirred for reaction; then an appropriate amount of ethylene glycol is added to remove unreacted sodium periodate, then a cerium salt is added, and stirred for 20-40 min to obtain a mixed solution, then a sodium hydroxide solution with a concentration of 0.1 mol / L is added dropwise to adjust the pH of the mixed solution to 7-9, then stirred at room temperature for 2-4 h, filtered, washed, and vacuum dried at 70-90 °C for 10-14 h to obtain the cerium oxidized tannate material; the molar ratio of tannic acid and cerium salt is 1:2-4; the cerium salt is at least one of cerium nitrate, cerium chloride, and cerium acetate.

[0021] Preferably, the stirring reaction time is 3 to 7 h, and the molar ratio of tannic acid to sodium periodate is 1:2 to 4.

[0022] Preferably, the concentration of the sodium hydroxide solution is 0.1 mol / L, the pH is 7 to 9, and the vacuum drying is carried out at 70 to 90 °C for 10 to 14 h.

[0023] Preferably, the molar ratio of tannic acid to cerium salt is 1:2 to 4; the cerium salt is at least one of cerium nitrate, cerium chloride, and cerium acetate.

[0024] Based on the above-mentioned preparation method of a degradable antibacterial plastic packaging bag, the preparation method includes the following steps: mixing polycaprolactone, polybutylene adipate terephthalate, Cr and Cu co-modified ZIF-8, and cerium oxide tannic acid materials evenly, and then adding the feed into a twin-screw extruder. The set parameters are as follows: the screw speed is 200 - 250 rpm, and the heating temperatures of zones 1 - 5 are as follows: 140 - 150 °C, 150 - 160 °C, 160 - 170 °C, 160 - 170 °C, 170 - 175 °C; then drying the granulated material at 50 - 70 °C for 8 - 12 h to obtain blown film materials, and then feeding them into a blown film machine to blow mold into films. The set parameters are as follows: the screw speed is 220 - 260 rpm, and the heating temperatures of zones 1 - 5 are as follows: 135 - 140 °C, 145 - 150 °C, 150 - 160 °C, 160 - 170 °C, 170 - 175 °C, and the traction speed is 8 - 10 m / min to make a plastic film. The plastic film is slit and made into bags to obtain a degradable antibacterial plastic packaging bag.

[0025] The present invention has the following beneficial effects:

[0026] In the present invention, by co-modifying ZIF-8 with Cr and Cu and utilizing the synergistic effect between Cr and Cu, the antibacterial performance of ZIF-8 itself is improved, and further the antibacterial performance of the packaging bag is enhanced. By adding cerium oxide tannic acid materials and utilizing the polyphenols on the surface of tannic acid and the antibacterial ion cerium, the two act together to make the packaging bag have excellent antibacterial performance. Moreover, the degradable antibacterial plastic packaging bag prepared by the present invention has excellent mechanical properties. Therefore, the degradable antibacterial plastic packaging bag prepared by the present invention has excellent antibacterial performance and good mechanical properties. Specific Embodiments

[0027] The following specific embodiments are used to further illustrate the present invention, but the embodiments do not limit the present invention in any form. Unless otherwise specified, the reagents, methods, and equipment used in the present invention are conventional reagents, methods, and equipment in the technical field.

[0028] Unless otherwise specified, the reagents and materials used in the following embodiments are all commercially available.

[0029] Example 1

[0030] A degradable antibacterial plastic packaging bag, by weight, comprises the following raw materials: 80 parts of polycaprolactone; 30 parts of poly(butylene adipate-co-terephthalate); 3 parts of Cr and Cu co-modified ZIF-8; 4 parts of cerium oxidized tannate material;

[0031] The preparation method of the Cr and Cu co-modified ZIF-8 comprises the following steps:

[0032] 0.04 mol of chromium nitrate, 0.03 mol of copper acetate, 1.5 mol of zinc chloride and 3.5 mol of 2-methylimidazole are ultrasonically dispersed in 200 mL of ethanol, stirred for 30 min, then hydrothermally treated at 160 °C for 15 h, filtered, washed, and vacuum dried at 80 °C for 18 h to obtain Cr and Cu co-modified ZIF-8;

[0033] The preparation method of the cerium oxidized tannate material comprises the following steps:

[0034] (1) 1 mol of tannic acid and 3 mol of sodium periodate are ultrasonically dispersed in 200 mL of deionized water, stirred and reacted for 5 h, then an appropriate amount of ethylene glycol is added to remove unreacted sodium periodate, then 3 mol of cerium nitrate is added, stirred for 30 min to obtain a mixed solution, then a sodium hydroxide solution with a concentration of 0.1 mol / L is added dropwise to adjust the pH of the mixed solution to 8, then stirred at room temperature for 3 h, filtered, washed, and vacuum dried at 80 °C for 12 h to obtain the cerium oxidized tannate material.

[0035] A preparation method of a degradable antibacterial plastic packaging bag, the preparation method comprises the following steps: polycaprolactone, poly(butylene adipate-co-terephthalate), Cr and Cu co-modified ZIF-8, and cerium oxidized tannate material are mixed evenly, then added to a twin-screw extruder, and the parameters are set as follows: screw speed 240 rpm, heating temperatures in zones 1-5 are as follows: 145 °C, 155 °C, 165 °C, 165 °C, 170 °C; then the granulated material is dried at 60 °C for 10 h to obtain blown film material, and then put into a blown film machine to blow and form a film, and the parameters are set as follows: screw speed 240 rpm, heating temperatures in zones 1-5 are as follows: 140 °C, 150 °C, 155 °C, 165 °C, 175 °C, traction speed 9 m / min, to make a plastic film, and the plastic film is slit and made into bags to obtain the degradable antibacterial plastic packaging bag.

[0036] Example 2

[0037] A degradable antibacterial plastic packaging bag, by weight, comprises the following raw materials: 90 parts of polycaprolactone; 20 parts of poly(butylene terephthalate-co-adipate); 5 parts of Cr and Cu co-modified ZIF-8; 2 parts of cerium oxidized tannate material;

[0038] The preparation method of the Cr and Cu co-modified ZIF-8 comprises the following steps:

[0039] 0.06 mol of chromium acetate, 0.01 mol of copper chloride, 1.5 mol of zinc nitrate and 4 mol of 2-methylimidazole are ultrasonically dispersed in 200 mL of ethanol, stirred for 40 min, then hydrothermally treated at 180 °C for 10 h, filtered, washed, and vacuum dried at 90 °C for 14 h to obtain Cr and Cu co-modified ZIF-8;

[0040] The preparation method of the cerium oxidized tannate material is the same as that in Example 1.

[0041] The preparation method of a degradable antibacterial plastic packaging bag is the same as that in Example 1.

[0042] Example 3

[0043] A degradable antibacterial plastic packaging bag, by weight, comprises the following raw materials: 70 parts of polycaprolactone; 40 parts of poly(butylene terephthalate-co-adipate); 1 part of Cr and Cu co-modified ZIF-8; 6 parts of cerium oxidized tannate material;

[0044] The preparation method of the Cr and Cu co-modified ZIF-8 comprises the following steps:

[0045] 0.02 mol of chromium chloride, 0.05 mol of copper nitrate, 1.5 mol of zinc acetate and 3 mol of 2-methylimidazole are ultrasonically dispersed in 200 mL of ethanol, stirred for 20 min, then hydrothermally treated at 140 °C for 20 h, filtered, washed, and vacuum dried at 60 °C for 20 h to obtain Cr and Cu co-modified ZIF-8;

[0046] The preparation method of the cerium oxidized tannate material is the same as that in Example 1.

[0047] The preparation method of a degradable antibacterial plastic packaging bag is the same as that in Example 1.

[0048] Comparative Example 1

[0049] Comparative Example 1 is basically the same as Example 1, except that: Cr and Cu are not added during the preparation of ZIF-8.

[0050] Comparative Example 2

[0051] Comparative Example 2 is basically the same as Example 1, except that: an equal amount of Cu-modified ZIF-8 is used to replace the Cr- and Cu-codoped ZIF-8. The preparation method of the Cu-modified ZIF-8 includes the following steps:

[0052] 0.07 mol of copper acetate, 1.5 mol of zinc chloride and 3.5 mol of 2-methylimidazole were ultrasonically dispersed in 200 mL of ethanol, stirred for 30 min, then hydrothermally treated at 160 °C for 15 h, filtered, washed, and vacuum dried at 80 °C for 18 h to obtain Cu-modified ZIF-8.

[0053] Comparative Example 3

[0054] Comparative Example 3 is basically the same as Example 1, except that: an equal amount of tannic acid is used to replace the cerium oxidized tannate material.

[0055] Comparative Example 4

[0056] Comparative Example 4 is basically the same as Example 1, except that: the cerium oxidized tannate material is used to replace the Cr- and Cu-codoped ZIF-8.

[0057] The properties of the degradable antibacterial plastic packaging bags of Examples 1-3 and Comparative Examples 1-4 were tested. The specific test results are shown in Table 1:

[0058] Among them, the tensile strength: was tested according to the national standard GB / T 1040.3-2006;

[0059] The antibacterial rate: was tested according to the standard QB / T2591-2003, and the test strain was Staphylococcus aureus.

[0060] Table 1

[0061]

[0062] As can be seen from 1, a degradable antibacterial plastic packaging bag prepared by the present invention has excellent antibacterial properties. From the comparison between the examples and the comparative examples, it can be seen that the antibacterial material selected by the present invention can significantly improve the antibacterial properties of the packaging bag, and has good mechanical properties.

[0063] The above embodiments are the preferred embodiments of the present invention, but the embodiments of the present invention are not limited by the above embodiments. Any other changes, modifications, substitutions, combinations, and simplifications made without departing from the spirit and principle of the present invention shall be equivalent replacement methods and are all included in the protection scope of the present invention.

Claims

1. A degradable antibacterial plastic packaging bag, characterized in that: By weight, it includes the following raw materials: 70-90 parts of polycaprolactone; 20-40 parts of poly(butylene terephthalate-co-adipate); 1-5 parts of Cr and Cu co-modified ZIF-8; 2-6 parts of cerium oxidized tannic acid material.

2. The degradable antibacterial plastic packaging bag according to claim 1, wherein: The preparation method of the Cr and Cu co-modified ZIF-8 includes the following steps: Ultrasonically disperse chromium salt, copper salt, zinc salt and 2-methylimidazole in ethanol, stir, then carry out hydrothermal treatment, filter, wash, and vacuum dry to obtain Cr and Cu co-modified ZIF-8.

3. The degradable antibacterial plastic packaging bag according to claim 2, characterized in that: The chromium salt is one of chromium nitrate, chromium acetate, and chromium chloride; the copper salt is one of copper nitrate, copper acetate, and copper chloride; the zinc salt is one of zinc nitrate, zinc acetate, and zinc chloride; the molar ratio of the chromium salt, copper salt, zinc salt and 2-methylimidazole is 0.02-0.06:0.01-0.05:1.5:3-4.

4. The degradable antibacterial plastic packaging bag according to claim 2, wherein: The stirring time is 20-40 min.

5. The biodegradable antibacterial plastic packaging bag according to claim 2, characterized in that: The conditions of the hydrothermal treatment are hydrothermal treatment at 140-180 °C for 10-20 h; the vacuum drying is vacuum drying at 60-90 °C for 14-20 h.

6. The biodegradable antibacterial plastic packaging bag according to claim 1, wherein: The preparation method of the cerium oxidized tannic acid material includes the following steps: Ultrasonically disperse tannic acid and sodium periodate into deionized water, stir and react; then add an appropriate amount of ethylene glycol to remove unreacted sodium periodate, then add cerium salt, stir for 20-40 min to obtain a mixed solution, then dropwise add sodium hydroxide solution to adjust the pH of the mixed solution, then stir at room temperature for 2-4 h, filter, wash, and vacuum dry to obtain the cerium oxidized tannic acid material.

7. The degradable antibacterial plastic packaging bag according to claim 6, characterized in that: The stirring reaction time is 3-7 h, and the molar ratio of tannic acid to sodium periodate is 1:2-4.

8. The biodegradable antibacterial plastic packaging bag according to claim 6, wherein: The concentration of the sodium hydroxide solution is 0.1 mol / L, the pH = 7-9, and the vacuum drying is vacuum drying at 70-90 °C for 10-14 h.

9. A degradable antibacterial plastic packaging bag according to any one of claims 6-8, characterized in that: The molar ratio of tannic acid to cerium salt is 1:2-4; the cerium salt is at least one of cerium nitrate, cerium chloride, and cerium acetate.

10. The preparation method of a degradable antibacterial plastic packaging bag according to any one of claims 1-9, characterized in that: The preparation method includes the following steps: Mix polycaprolactone, poly(butylene terephthalate-co-adipate), Cr and Cu co-modified ZIF-8, and cerium oxidized tannic acid material evenly, then add the feedstock into a twin-screw extruder, and set the parameters as follows: the screw speed is 200-250 rpm, and the heating temperatures in zones 1-5 are as follows: 140-150 °C, 150-160 °C, 160-170 °C, 160-170 °C, 170-175 °C; then dry the pelletized material at 50-70 °C for 8-12 h to obtain blown film material, and then put it into a blown film machine to blow and form a film, and set the parameters as follows: the screw speed is 220-260 rpm, and the heating temperatures in zones 1-5 are as follows: 135-140 °C, 145-150 °C, 150-160 °C, 160-170 °C, 170-175 °C, and the traction speed is 8-10 m / min to make a plastic film, and the plastic film is slit and bagged to obtain a degradable antibacterial plastic packaging bag.

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