High-sealing antibacterial packaging inner film, preparation method thereof and paper box

Abstract

The invention relates to the field of packaging materials, and particularly discloses a high-sealing antibacterial packaging inner film, a preparation method thereof and a paper box. The high-sealing antibacterial packaging inner film is prepared from the following raw materials: 20 to 30g of nano cellulose, 2 to 6g of modified zinc-based nano particles, 10 to 14g of modified diatomite and 45 to 55ml of deionized water, the modified zinc-based nano particles are loaded on the modified diatomite, and the modified zinc-based nano particles contain a silane coupling agent. The high-sealing antibacterial packaging inner film, the preparation method thereof and the paper box have the advantage that the defect that the antibacterial performance of the packaging inner film is still insufficient can be overcome.

Description

Technical Field

[0001] The present application relates to the field of packaging materials, and more specifically, to a highly sealed antibacterial packaging inner film, a preparation method thereof, and a paper box. Background Art

[0002] In recent years, people's awareness of environmental protection and food safety has been continuously enhanced. Compared with traditional plastic packaging materials, green packaging materials that conform to the principle of sustainable development and have higher safety are more favored and play an important role in aspects such as food preservation, oxygen isolation, moisture proof, dust prevention, and dirt prevention. However, currently, traditional packaging inner films are difficult to degrade quickly and will cause pollution to the environment.

[0003] In order to enable the packaging inner film to reduce environmental pollution, cellulose with certain barrier properties is often selected as the base material. Cellulose is a green, biodegradable, and environmentally friendly natural polymer, but cellulose lacks antibacterial function. Therefore, nanoparticles with antibacterial properties are selected to improve the antibacterial function of cellulose. However, due to the high surface energy performance of nanoparticles, they are prone to agglomeration, which may not easily improve the antibacterial performance of the packaging inner film. Summary of the Invention

[0004] In order to improve the defect that the antibacterial performance of the packaging inner film is still insufficient, the present application provides a highly sealed antibacterial packaging inner film, a preparation method thereof, and a paper box.

[0005] In the first aspect, a highly sealed antibacterial packaging inner film provided by the present application adopts the following technical solution: A highly sealed antibacterial packaging inner film includes the following raw materials: 22 - 30 g of nanocellulose, 2 - 6 g of modified zinc-based nanoparticles, 10 - 14 g of modified diatomite, and 45 - 55 ml of deionized water. The modified zinc-based nanoparticles are loaded on the modified diatomite, and the modified zinc-based nanoparticles contain a silane coupling agent.

[0006] Since nanocellulose has good mechanical strength and barrier properties, nanocellulose itself has a certain sealing property. Nanocellulose is mainly composed of glucose units connected by β-1,4-glycosidic bonds, and its chemical structure is a polysaccharide substance and does not have antibacterial properties itself. Since zinc-based nanoparticles will slowly release zinc ions in a humid environment, and zinc ions can penetrate the bacterial cell membrane and bind to proteins, enzymes, and DNA in bacteria, interfering with their metabolic activities. Therefore, when zinc-based nanoparticles are compounded with nanocellulose, zinc ions can be continuously released from the composite material, thereby improving the antibacterial performance of nanocellulose.

[0007] Due to the large specific surface area and high surface energy of zinc-based nanoparticles, agglomeration is likely to occur between the particles, which affects the antibacterial property of the inner packaging film. Silane coupling agents can modify the surface of zinc-based nanoparticles, introduce organic groups, improve the dispersibility of zinc-based nanoparticles, and thus enhance the antibacterial property of the inner packaging film.

[0008] Due to the large specific surface area, high porosity, and good adsorption performance of diatomite, the modified zinc-based nanoparticles can be evenly loaded on the diatomite, further improving the dispersibility of the modified zinc-based nanoparticles. At the same time, due to the excellent adsorption performance of diatomite, it can adsorb harmful gases or moisture in the package, further enhancing the sealing property of the inner packaging film.

[0009] Preferably, the silane coupling agent is KBM-603.

[0010] Since KBM-603 is a silane coupling agent containing an amino group, one end of its molecular structure is a siloxane group and the other end is an amino group. The siloxane group can chemically react with the hydroxyl groups on the surface of zinc-based nanoparticles to form stable chemical bonds, and the amino group provides an organically functionalized surface, enhancing the compatibility and dispersibility of zinc-based nanoparticles in the organic system.

[0011] Preferably, the modified zinc-based nanoparticles include the following raw materials: 90-110 g of KBM-603 and 95-105 g of zinc oxide nanospheres.

[0012] Due to the high specific surface area of zinc oxide nanospheres, the high specific surface area is conducive to improving the release rate of zinc ions and the generation efficiency of reactive oxygen species, providing more active sites, thus enhancing the contact efficiency with bacteria and improving the antibacterial property of the inner packaging film.

[0013] Preferably, the preparation method of the modified zinc-based nanoparticles: Weigh 90-110 g of KBM-603 and heat it in an oil bath to turn it into steam. Pass the steam coupling agent into a three-necked flask containing 95-105 g of zinc oxide nanospheres, heat it in an oil bath and stir for 1-3 h to obtain the modified zinc-based nanoparticles.

[0014] By heating KBM-603 into steam, its siloxane group chemically reacts with the hydroxyl groups on the surface of zinc oxide nanospheres to form stable Si-O-Zn bonds, completing the modification of nano-zinc oxide. At the same time, heating KBM-603 into steam can also reduce the waste of the modifier and eliminate the process of separating excess modifier and solvent.

[0015] Preferably, the modified diatomite includes the following raw materials: 3-7 g of diatomite, 0.5-2.5 g of chitosan, 40-60 ml of acetic acid solution, and 100-300 ml of sodium hydroxide solution.

[0016] Due to the porous structure and high specific surface area of diatomite, chitosan can be adsorbed on its surface and in the voids. Moreover, the hydroxyl and amino groups on the chitosan molecular chain can form hydrogen bonds with the silanol groups on the surface of diatomite, further enhancing the adsorption. The composite of chitosan and cellulose can form a dense and ordered hydrogen bond network structure, which is beneficial to further improving the barrier performance of the inner packaging film.

[0017] Preferably, the preparation method of the modified diatomite is as follows: Weigh 0.5 - 2.5 g of chitosan and slowly add it to 40 - 60 ml of acetic acid solution to dissolve, then add 3 - 7 g of diatomite, stir for 1 - 3 h, then filter and freeze for 3 - 7 h, then freeze-dry for 22 - 26 h. After freeze-drying and forming, soak it in 100 - 300 ml of sodium hydroxide solution for 10 - 14 h, then soak it in deionized water and wash until neutral, and then freeze-dry to obtain the modified diatomite.

[0018] In the second aspect, the present application provides a preparation method of a highly sealed antibacterial packaging inner film, adopting the following technical solution: A preparation method of a highly sealed antibacterial packaging inner film, the following steps: S1: Weigh 2 - 6 g of modified zinc-based nanoparticles and dissolve them in 45 - 55 ml of deionized water, then add 10 - 14 g of modified diatomite and stir at room temperature for 10 - 14 h, then perform freeze-drying. Grind the freeze-dried product in a ball mill at a rotation speed of 250 - 350 rpm for 2 - 6 h; S2: Weigh 1 g - 2.4 g of the product obtained in S1 and add it to 22 - 30 g of nanofibrillated cellulose, and stir and disperse it evenly at a rotation speed of 200 - 300 rpm for 25 - 35 min to obtain a film-forming solution; S3: Pour the film-forming solution obtained in S2 into a polytetrafluoroethylene mold and dry it at room temperature for 3.5 - 4.5 days to obtain the packaging inner film.

[0019] In the third aspect, the present application provides a paper box, adopting the following technical solution: A paper box, comprising a highly sealed antibacterial packaging inner film and a paper box body.

[0020] In summary, the present application has the following beneficial effects: 1. Since nanocellulose has good mechanical strength and barrier properties, it has a certain sealing property itself. Nanocellulose is mainly composed of glucose units connected by β-1,4-glycosidic bonds, and its chemical structure is a polysaccharide substance, which does not have antibacterial properties itself. Since zinc-based nanoparticles will slowly release zinc ions in a humid environment, and zinc ions can penetrate the bacterial cell membrane and bind to proteins, enzymes and DNA in bacteria, interfering with their metabolic activities. Therefore, when zinc-based nanoparticles are combined with nanocellulose, zinc ions can be continuously released from the composite material, thereby improving the antibacterial performance of nanocellulose.

[0021] Because zinc-based nanoparticles have a large specific surface area and high surface energy, it is easy for particles to agglomerate, which affects the antibacterial property of the inner packaging film. And silane coupling agent can modify the surface of zinc-based nanoparticles, introduce organic groups, improve the dispersion of zinc-based nanoparticles, and thus improve the antibacterial property of the inner packaging film.

[0022] Because diatomite has a large specific surface area, high porosity and good adsorption performance, it can uniformly load modified zinc-based nanoparticles on diatomite, thereby further improving the dispersion of modified zinc-based nanoparticles. At the same time, due to the excellent adsorption performance of diatomite, it can adsorb harmful gases or moisture in the package, thereby further improving the sealing property of the inner packaging film.

[0023] 2. Since KBM-603 is a silane coupling agent containing amino groups, one end of its molecular structure is a siloxane group and the other end is an amino group. The siloxane group can chemically react with the hydroxyl groups on the surface of zinc-based nanoparticles to form stable chemical bonds, and the amino group provides an organically functionalized surface, enhancing the compatibility and dispersion of zinc-based nanoparticles in the organic system.

[0024] 3. Since zinc oxide nanospheres have a high specific surface area, a high specific surface area is beneficial to improving the release rate of zinc ions and the generation efficiency of reactive oxygen species, and can provide more active sites, thereby enhancing the contact efficiency with bacteria and improving the antibacterial property of the inner packaging film. Specific embodiments

[0025] The present application will be further described in detail below with reference to Examples 1-8 and Comparative Examples 1-3. Raw materials

[0026] Nanocellulose, Hubei Shineng Chemical Technology Co., Ltd.; KBM-603, Shanghai David New Materials Co., Ltd.; Sodium citrate dihydrate, Xilong Scientific Co., Ltd.; Hexamethylenetetramine, Fuchen (Tianjin) Chemical Reagent Co., Ltd.; Zinc acetate dihydrate, CAS: 5970-45-6; Diatomite, CAS: 68855-54-9; Chitosan, CAS: 9012-76-4; Acetic acid, CAS: 64-19-7; Sodium hydroxide, Xilong Scientific Co., Ltd.; Deionized water, CAS: 7732-18-5. Example 1

[0027] A highly sealed antibacterial packaging inner film, comprising the following raw materials: 25 g of nanocellulose, 4 g of modified zinc-based nanoparticles, 12 g of modified diatomite, and 50 ml of deionized water.

[0028] Specifically, the preparation method of the highly sealed antibacterial packaging inner film comprises the following steps: S1: Weigh 100 g of KBM-603 and heat it in an oil bath to turn it into steam. Pass the steam coupling agent into a three-necked flask containing 100 g of zinc oxide nanospheres, heat it in an oil bath and stir for 2 h to obtain modified zinc-based nanoparticles; S2: Weigh 1.5 g of chitosan and slowly add it to 50 ml of 1% acetic acid solution to dissolve it. Then add 5 g of diatomite and stir for 2 h. Subsequently, filter and freeze it for 5 h, then freeze-dry it for 24 h. After freeze-drying and forming, soak it in 200 ml of sodium hydroxide solution for 12 h, then soak it in deionized water and wash it until neutral, and then freeze-dry it to obtain modified diatomite; S3: Weigh 2 - 6 g of modified zinc-based nanoparticles and dissolve them in 45 - 55 ml of deionized water. Then add 10 - 14 g of modified diatomite and stir at room temperature for 10 - 14 h, and then perform freeze-drying. Grind the freeze-dried product in a ball mill at a rotation speed of 250 - 350 rpm for 2 - 6 h; S4: Weigh 1 g - 2.4 g of the product obtained in S1 and add it to 20 - 30 g of nanocellulose, stir and disperse it evenly at a rotation speed of 200 - 300 rpm for 25 - 35 min to obtain a film-forming solution; S5: Pour the film-forming solution obtained in S2 into a polytetrafluoroethylene mold and dry it at room temperature for 3.5 - 4.5 days to obtain the packaging inner film; Among them, the nanocellulose is a dispersion with a solid content of 0.8 wt%; Among them, the preparation method of zinc oxide nanospheres includes the following steps: Weigh 1.5 g of sodium citrate dihydrate, 7 g of hexamethylenetetramine, and 11 g of zinc acetate dihydrate into a beaker, add deionized water to make the concentration 1:10:10, stir for 30 min, then transfer the beaker to an oven, the reaction temperature is 95 °C, the time is 4 h, after cooling to room temperature, centrifuge the sample, the centrifuge speed is 4000 r / min, the centrifuge time is 3 min, then dry in an oven at 60 °C for 8 h, and then calcine in a muffle furnace at 400 °C for 30 min to obtain spherical zinc oxide nanopowder.

[0029] Examples 2 - Examples 3 The difference from Example 1 is that the addition amounts of the components of the high-sealing antibacterial packaging inner film are different, as specifically shown in Table 1.

[0030] Table 1 Addition amounts of the components of the high-sealing antibacterial packaging inner film in Examples 1 - 3

[0031] Examples 4 - Examples 5 The difference from Example 1 is that the addition amounts of the components of the modified zinc-based nanoparticles are different, as specifically shown in Table 2.

[0032] Table 2 Addition amounts of the components of the modified zinc-based nanoparticles in Example 1 and Examples 4 - 5 (g)

[0033] Example 6 The difference from Example 1 is that KBM-603 is replaced with KH-560 with the same addition amount.

[0034] Examples 7 - Examples 8 The difference from Example 1 is that the addition amounts of the components of the modified diatomite are different, as specifically shown in Table 3.

[0035] Table 3 Addition amounts of the components of the modified diatomite in Example 1 and Examples 7 - 8

[0036] Comparative Example 1 The difference from Example 1 is that the modified zinc-based nanoparticles are replaced with zinc-based nanoparticles with the same addition amount.

[0037] Comparative Example 2 The difference from Example 1 is that the modified diatomite is no longer added.

[0038] Comparative Example 3 It is different from Example 1 in that modified zinc-based nanoparticles and modified diatomite are no longer added. Performance detection test

[0039] I. Antibacterial performance test Three samples were taken from Examples 1-8 and Comparative Examples 1-3 respectively, and the antibacterial performance test was carried out with reference to QB / T2591-2003 "Antibacterial Plastics - Test Methods for Antibacterial Performance and Antibacterial Effects".

[0040] The test data are shown in Table 4.

[0041] Table 4 Antibacterial performance test table of Examples 1-8 and Comparative Examples 1-3 (%)

[0042] Combining Example 1 and Comparative Example 3 and referring to Table 4, it can be seen that compared with Example 1, the initial antibacterial rates of Comparative Example 1 against Escherichia coli and Staphylococcus aureus are significantly reduced, and the antibacterial rate after 48 days is also significantly reduced compared with the initial antibacterial rate. This shows that compared with conventional nanocellulose, the inner packaging film obtained by compounding nanocellulose with modified zinc-based nanoparticles and modified diatomite also has excellent antibacterial performance.

[0043] The reason is that since zinc-based nanoparticles will slowly release zinc ions in a humid environment, and zinc ions can penetrate the bacterial cell membrane and bind to proteins, enzymes and DNA in the bacteria, interfering with their metabolic activities. Therefore, when zinc-based nanoparticles are compounded with nanocellulose, zinc ions can be continuously released from the composite material, thereby improving the antibacterial performance of nanocellulose. At the same time, diatomite has a large specific surface area, high porosity and good adsorption performance, and can evenly load modified zinc-based nanoparticles on diatomite, thereby further improving the dispersibility of modified zinc-based nanoparticles. At the same time, due to the excellent adsorption performance of diatomite, it can adsorb harmful gases or moisture in the packaging, thereby further improving the sealing performance of the inner packaging film.

[0044] Combining Example 1 and Comparative Example 1 and referring to Table 4, it can be seen that compared with Example 1, the initial antibacterial rates of Comparative Example 1 against Escherichia coli and Staphylococcus aureus are significantly reduced, and the antibacterial rate after 48 days is also significantly reduced compared with the initial antibacterial rate. This shows that compared with adding conventional zinc-based nanoparticles, adding modified zinc-based nanoparticles can effectively improve the antibacterial performance of the inner packaging film.

[0045] The reason is that due to the large specific surface area and high surface energy of zinc-based nanoparticles, agglomeration is likely to occur between the particles, which affects the antibacterial property of the inner packaging film. While silane coupling agents can modify the surface of zinc-based nanoparticles, introduce organic groups, improve the dispersibility of zinc-based nanoparticles, and thus enhance the antibacterial property of the inner packaging film.

[0046] Combining Example 1 and Comparative Example 2 and referring to Table 4, it can be seen that compared with Example 1, the initial antibacterial rates of Comparative Example 2 against Escherichia coli and Staphylococcus aureus are significantly reduced. At the same time, the antibacterial rates after 48 days are also significantly lower than the initial antibacterial rates. This shows that adding modified diatomaceous earth can effectively improve the antibacterial performance of the inner packaging film compared with not adding modified diatomaceous earth.

[0047] Combining Example 1 and Examples 2 - 3 and referring to Table 4, it can be seen that compared with Example 1, the initial antibacterial rates of Examples 2 and 3 against Escherichia coli and Staphylococcus aureus are reduced to some extent. At the same time, the antibacterial rates after 48 days are also lower than the initial antibacterial rates. This indicates that the addition amounts of the components of the high-sealing antibacterial inner packaging film affect the antibacterial performance of the inner packaging film, and the addition amounts of the components of the high-sealing antibacterial inner packaging film in Example 1 are the optimal ones.

[0048] Combining Example 1 and Examples 4 - 5 and referring to Table 4, it can be seen that compared with Example 1, the initial antibacterial rates of Examples 4 and 5 against Escherichia coli and Staphylococcus aureus are reduced to some extent. At the same time, the antibacterial rates after 48 days are also lower than the initial antibacterial rates. This shows that the addition amounts of the components of the modified zinc-based nanoparticles affect the antibacterial performance of the inner packaging film, and the addition amounts of the components of the modified zinc-based nanoparticles in Example 1 are the optimal ones.

[0049] Combining Example 1 and Example 6 and referring to Table 4, it can be seen that compared with Example 1, the initial antibacterial rates of Example 6 against Escherichia coli and Staphylococcus aureus are significantly reduced. At the same time, the antibacterial rates after 48 days are also significantly lower than the initial antibacterial rates. This shows that compared with adding KH-560, the addition of KBM-603 can effectively improve the antibacterial performance of the inner packaging film.

[0050] The reason is that since KBM-603 is a silane coupling agent containing amino groups, one end of its molecular structure is a siloxy group and the other end is an amino group. The siloxy group can chemically react with the hydroxyl groups on the surface of zinc-based nanoparticles to form stable chemical bonds, and the amino group provides an organically functionalized surface, enhancing the compatibility and dispersibility of zinc-based nanoparticles in the organic system.

[0051] Combined with Example 1 and Examples 7 - 8 and Table 4, it can be seen that compared with Example 1, the initial antibacterial rates of Example 7 and Example 8 against Escherichia coli and Staphylococcus aureus are both reduced. At the same time, the antibacterial rate after 48 days is also lower than the initial antibacterial rate. This shows that the addition amount of each component of the modified diatomite affects the antibacterial performance of the inner packaging film, and the addition amount of each component of the modified diatomite in Example 1 is the optimal one.

[0052] This specific embodiment is only an interpretation of the present application and does not limit the present application. After reading this specification, those skilled in the art can make modifications to this embodiment without creative contributions as needed, but as long as it is within the scope of the claims of the present application, it is protected by the patent law.

Claims

1. A highly sealed antibacterial packaging inner membrane, characterized in that, It includes the following raw materials: 20 - 30 g of nanocellulose, 2 - 6 g of modified zinc - based nanoparticles, 10 - 14 g of modified diatomaceous earth, and 45 - 55 ml of deionized water. The modified zinc - based nanoparticles are loaded on the modified diatomaceous earth, and the modified zinc - based nanoparticles contain a silane coupling agent.

2. The inner film of a highly sealed antibacterial package according to claim 1, characterized in that: The silane coupling agent is KBM - 603.

3. The high-sealing antibacterial packaging inner membrane according to claim 2, characterized in that, The modified zinc - based nanoparticles include the following raw materials: 90 - 110 g of KBM - 603 and 95 - 105 g of zinc oxide nanospheres.

4. The inner film of a highly sealed antibacterial package according to claim 3, characterized in that, The preparation method of the modified zinc - based nanoparticles: Weigh 90 - 110 g of KBM - 603 and heat it in an oil bath to make it into steam. Then, introduce the steam coupling agent into a three - necked flask containing 95 - 105 g of zinc oxide nanospheres, heat it in an oil bath and stir for 1 - 3 h to obtain the modified zinc - based nanoparticles.

5. The high-sealing antibacterial packaging inner film according to claim 4, characterized in that, The modified diatomaceous earth includes the following raw materials: 3 - 7 g of diatomaceous earth, 0.5 - 2.5 g of chitosan, 40 - 60 ml of acetic acid solution, 100 - 300 ml of sodium hydroxide solution.

6. The high-sealing antibacterial packaging inner film according to claim 5, characterized in that, The preparation method of the modified diatomaceous earth: Weigh 0.5 - 2.5 g of chitosan and slowly add it to 40 - 60 ml of acetic acid solution to dissolve. Then add 3 - 7 g of diatomaceous earth and stir for 1 - 3 h. Subsequently, filter and freeze it for 3 - 7 h. Then, freeze - dry it for 22 - 26 h. After freeze - drying and forming, soak it in 100 - 300 ml of sodium hydroxide solution for 10 - 14 h, then soak it in deionized water and wash it until neutral, and then freeze - dry to obtain the modified diatomaceous earth.

7. The preparation method of a highly sealed antibacterial packaging inner film according to any one of claims 1-6, characterized in that, It includes the following steps: S1: Weigh 2 - 6 g of modified zinc - based nanoparticles and dissolve them in 45 - 55 ml of deionized water. Then add 10 - 14 g of modified diatomaceous earth and stir at room temperature for 10 - 14 h. Then, conduct freeze - drying. Grind the freeze - dried product in a ball mill at a rotation speed of 250 - 350 rpm for 2 - 6 h. S2: Weigh 1 g - 2.4 g of the product obtained in S1 and add it to 20 - 30 g of nanocellulose. Stir and disperse it evenly at a rotation speed of 200 - 300 rpm for 25 - 35 min to obtain a film - forming solution. S3: Pour the film - forming solution obtained in S2 into a polytetrafluoroethylene mold and dry it at room temperature for 3.5 - 4.5 days to obtain an inner packaging film.

8. A paper box, characterized in that, It includes a high - sealing antibacterial inner packaging film and a paper - box body as described in any one of claims 1 - 7.

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