Graphene antibacterial paperboard and preparation method thereof

Abstract

The invention relates to the technical field of antibacterial packaging, and provides a graphene antibacterial paperboard and a preparation method thereof.The graphene antibacterial paperboard is prepared from, by weight, 0.1-0.6 part of graphene oxide, 0.1-1 part of polymeric quaternary ammonium salt, 3-8 parts of a sizing agent, 0.05-0.1 part of cationic polyacrylamide, 90-100 parts of wood pulp and 0.2-1.8 parts of L-phenylalaninol. According to the technical scheme, the problems of low strength and low antibacterial property of the paperboard in the prior art are solved.

Description

Technical Field

[0001] The present invention relates to the technical field of antibacterial packaging, and in particular to a graphene antibacterial paperboard and a preparation method thereof. Background Art

[0002] With the rapid development of modern packaging technology, a number of new food packaging boxes with different functions have been launched on the market and are increasingly being adopted by the food industry.

[0003] Hokkaido Hankan Fisheries Co., Ltd. in Japan has developed a fresh-keeping box for transporting live shrimps. The product adopts a three-layer structure: the inner layer is a watertight vinyl box, which contains water and live shrimps; the outer layer is made of foam styrene, and there is a space of about 5 cm between the two layers, which is used to place crushed ice or chemical refrigeration. The inner box is filled with seawater that has been sterilized and injected with a certain amount of oxygen. The live shrimps can be placed in the water and covered tightly for transportation, with a fresh-keeping survival rate of over 90%.

[0004] The Japan Food Distribution Systems Association recently developed a fruit and vegetable fresh-keeping packaging box, which uses "Ristovar stone", a type of silicate that has a good adsorption effect on various gases, as an additive to the pulp. Therefore, fruits and vegetables packaged in this carton can be kept fresh for a longer period of time and are suitable for long-distance storage and transportation.

[0005] The above technologies use low temperature and adsorption to preserve food and cannot actively resist bacteria. During transportation and storage, if the cardboard box cannot effectively prevent the spread of bacteria and effectively resist the growth of bacteria and microorganisms, it may cause cross-infection between different products, increase the risk of disease transmission; cause packaged food to be contaminated by bacteria, thereby affecting food safety; cause goods to rot or deteriorate, resulting in cargo losses. In view of the problems existing in existing functional packaging boxes, the development of a high-strength antibacterial cardboard is an issue that needs to be solved urgently. Summary of the invention

[0006] The present invention provides a graphene antibacterial paperboard and a preparation method thereof, which solves the problems of low strength and low antibacterial performance of paperboard in the related art.

[0007] The technical solution of the present invention is as follows: The present invention proposes a graphene antibacterial paperboard, comprising the following component raw materials in parts by weight: 0.1-0.6 parts of graphene oxide, 0.1-1 parts of polymerized quaternary ammonium salt, 3-8 parts of sizing agent, 0.05-0.1 parts of cationic polyacrylamide, 90-100 parts of wood pulp, and 0.2-1.8 parts of L-phenylalaninol.

[0008] As a further technical solution, the graphene oxide consists of a first graphene oxide and a second graphene oxide, and the first graphene oxide and the second graphene oxide have different oxygen contents.

[0009] As a further technical solution, the oxygen content of the first graphene oxide is 30wt%, and the oxygen content of the second graphene oxide is 45wt%.

[0010] As a further technical solution, the mass ratio of the first graphene oxide to the second graphene oxide is 1-3:1.

[0011] As a further technical solution, the mass ratio of the first graphene oxide to the second graphene oxide is 2:1.

[0012] The oxygen content has an important influence on various properties of graphene oxide. A lower oxygen content usually means higher conductivity and mechanical toughness, while a graphene oxide with a higher oxygen content usually has better optical properties and mechanical rigidity. The present invention reasonably controls the oxygen content of graphene oxide, gives full play to its advantages and minimizes the negative effects that may be caused by its excessively high oxygen content, thereby obtaining a paperboard with the greatest strength and the best antibacterial effect.

[0013] As a further technical solution, the number of layers of the graphene oxide is 3 to 5, and the median diameter is less than 1 μm.

[0014] As a further technical solution, the polymeric quaternary ammonium salt includes one or both of pharmaceutical grade polydimethyldiallylammonium chloride and pharmaceutical grade polyquaternary ammonium urea-containing polymer.

[0015] As a further technical solution, the sizing agent includes one or both of modified starch and polyvinyl alcohol.

[0016] As a further technical solution, the mass ratio of L-phenylalaninol to graphene oxide is 3-5:1.

[0017] As a further technical solution, the mass ratio of L-phenylalaninol to graphene oxide is 4:1.

[0018] The present invention also provides a method for preparing a graphene antibacterial paperboard, comprising the following steps: S1, after mixing graphene oxide with water, adding polymerized quaternary ammonium salt, dispersing evenly and drying to obtain surface pretreated graphene oxide; S2, mixing the surface pretreated graphene oxide, cationic polyacrylamide, wood pulp, and L-phenylalaninol to obtain a slurry; S3, slurry forming, pressing, drying, calendering, single-sided gluing to obtain paperboard.

[0019] As a further technical solution, the drying temperature in S1 is 80-120 min.

[0020] As a further technical solution, the mixing in S1 is ultrasonic mixing, the power of the ultrasound is 20kHz-40kHz, and the time of the ultrasound is 30min.

[0021] As a further technical solution, the dispersion in S1 is ultrasonic dispersion, the power of the ultrasound is 20kHz-40kHz, and the ultrasound time is 30 minutes.

[0022] As a further technical solution, the mixing in S2 is mechanical stirring, and the time of the mechanical stirring is 60 minutes.

[0023] As a further technical solution, the concentration of the slurry is 3wt%~3.5wt%.

[0024] As a further technical solution, the dryness after drying in step S3 is 92-95%.

[0025] The working principle and beneficial effects of the present invention are: In the present invention, the added graphene oxide material has the function of radiating far infrared rays of relevant frequencies, and the manufactured paperboard has a far infrared emissivity of not less than 85%, and has a strong far infrared emission capability. The far infrared rays emitted by the material are used to sterilize and protect the food in the package, thereby blocking harmful bacteria from entering the packaging box from the outside, causing the corruption of the food, and effectively improving the antibacterial performance of the paperboard. In the present invention, L-phenylalaninol is also added, and L-phenylalaninol can be combined with the fiber in the wood pulp through hydrogen bonds, and cross-linked with graphene oxide to enhance the interaction between the three. In addition, the benzene ring structure contained in L-phenylalaninol can also increase the van der Waals interaction between it and the fiber, which helps to improve its dispersibility and stability in the pulp, thereby improving the mechanical strength of the paper; L-phenylalaninol also has certain antibacterial properties, and can play an antibacterial role by destroying the microbial cell membrane, interfering with the metabolism of substances in the cell, and further improving the antibacterial performance of the paperboard. DETAILED DESCRIPTION

[0026] The following will be combined with the embodiments of the present invention to clearly and completely describe the technical solutions in the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0027] In the following examples and comparative examples: Cationic polyacrylamide: 160 mesh, manufactured by Henan Wanjiang Environmental Protection Technology Co., Ltd.; Polydimethyldiallylammonium chloride: pharmaceutical grade, manufactured by Hubei Qifei Pharmaceutical Chemical Co., Ltd. Polyquaternary ammonium urea polymer: pharmaceutical grade, manufactured by Wuhan Huajiu Pharmaceutical Technology Co., Ltd. The first graphene oxide: oxygen content 30wt%, model GX-p-GO-1, manufacturer Hangzhou Gaoxun Technology Co., Ltd.; Second graphene oxide: oxygen content 45wt%, model HQNANO-GR-005-2, manufacturer Suzhou Carbon Graphene Technology Co., Ltd.; Polyvinyl alcohol: model is PVA-2488, manufacturer is Tianjin Boteng New Materials Co., Ltd. Example

[0028] S1, weigh 0.1 parts of the first graphene oxide, add it to 10 parts of water, ultrasonic power 20kHz, disperse for 30 minutes, add 0.1 parts of polydimethyldiallylammonium chloride, continue to disperse for 30 minutes, and dry at 80°C to obtain surface pretreated graphene oxide; S2, mechanically stirring the surface pretreated graphene oxide, 0.05 parts of cationic polyacrylamide, 0.2 parts of L-phenylalaninol, and 96.75 parts of wood pulp for 60 minutes to induce the graphene oxide to adhere to the wood pulp fibers and mix the slurry evenly, and then adding water to adjust the concentration to 3.0wt% to obtain a slurry; S3, slurry forming, pressing, drying to a dryness of 92%, calendering, and sizing 3 parts of modified starch on one side to obtain the desired paperboard. Example

[0029] S1, weigh 0.3 parts of the first graphene oxide, add it to 30 parts of water, ultrasonic power 30kHz, disperse for 30 minutes, add 0.5 parts of polydimethyldiallylammonium chloride, continue to disperse for 30 minutes, and dry at 100°C to obtain surface pretreated graphene oxide; S2, mechanically stirring the surface pretreated graphene oxide, 0.07 parts of cationic polyacrylamide, 0.6 parts of L-phenylalaninol, and 94.13 parts of wood pulp for 60 minutes to induce the graphene oxide to adhere to the wood pulp fibers and mix the slurry evenly, and then adding water to adjust the concentration to 3.3wt% to obtain a slurry; S3, slurry forming, pressing, drying to a dryness of 94%, calendering, and sizing 5 parts of modified starch on one side to obtain the desired paperboard. Example

[0030] S1, weigh 0.6 parts of the first graphene oxide, add it to 60 parts of water, ultrasonic power 40kHz, disperse for 30 minutes, add 1 part of polyquaternary ammonium urea polymer, continue to disperse for 30 minutes, and dry at 120°C to obtain surface pretreated graphene oxide; S2, mechanically stirring the surface pretreated graphene oxide, 0.1 parts of cationic polyacrylamide, 1.2 parts of L-phenylalaninol, and 90.3 parts of wood pulp for 60 minutes to induce the graphene oxide to adhere to the wood pulp fibers and mix the slurry evenly, and then adding water to adjust the concentration to 3.5wt% to obtain a slurry; S3, slurry forming, pressing, drying to a dryness of 95%, calendering, and sizing 8 parts of polyvinyl alcohol on one side to obtain the desired paperboard. Example

[0031] Compared with Example 2, the difference of Example 4 is that 0.3 parts of the first graphene oxide is replaced by an equal amount of the second graphene oxide. Example

[0032] Compared with Example 2, the difference in Example 5 is that 0.3 parts of the first graphene oxide is replaced by 0.2 parts of the first graphene oxide and 0.1 parts of the second graphene oxide. Example

[0033] Compared with Example 2, the difference in Example 6 is that 0.3 parts of the first graphene oxide is replaced by 0.15 parts of the first graphene oxide and 0.15 parts of the second graphene oxide. Example

[0034] Compared with Example 2, the difference in Example 7 is that 0.3 parts of the first graphene oxide is replaced by 0.1 parts of the first graphene oxide and 0.2 parts of the second graphene oxide. Example

[0035] Compared with Example 2, the difference in Example 8 is that 0.3 parts of the first graphene oxide is replaced by 0.225 parts of the first graphene oxide and 0.075 parts of the second graphene oxide. Example

[0036] Compared with Example 2, the difference in Example 9 is that 0.3 parts of the first graphene oxide is replaced by 0.24 parts of the first graphene oxide and 0.06 parts of the second graphene oxide. Example

[0037] Compared with Example 7, the difference in Example 10 is that 0.1 parts of the first graphene oxide, 0.2 parts of the second graphene oxide, and 0.6 parts of L-phenylalaninol are replaced by 0.075 parts of the first graphene oxide, 0.15 parts of the second graphene oxide, and 0.675 parts of L-phenylalaninol. Example

[0038] Compared with Example 7, the difference in Example 11 is that 0.1 parts of the first graphene oxide, 0.2 parts of the second graphene oxide, and 0.6 parts of L-phenylalaninol are replaced with 0.06 parts of the first graphene oxide, 0.12 parts of the second graphene oxide, and 0.72 parts of L-phenylalaninol. Example

[0039] Compared with Example 7, the difference in Example 12 is that 0.1 parts of the first graphene oxide, 0.2 parts of the second graphene oxide, and 0.6 parts of L-phenylalaninol are replaced by 0.05 parts of the first graphene oxide, 0.1 parts of the second graphene oxide, and 0.75 parts of L-phenylalaninol. Example

[0040] Compared with Example 7, the difference in Example 13 is that 0.1 parts of the first graphene oxide, 0.2 parts of the second graphene oxide, and 0.6 parts of L-phenylalaninol are replaced by 0.04 parts of the first graphene oxide, 0.08 parts of the second graphene oxide, and 0.78 parts of L-phenylalaninol.

[0041] Comparative Example 1 Compared with Example 2, the difference in Comparative Example 1 is that L-phenylalaninol is not added.

[0042] The graphene antibacterial paperboards prepared in Examples 1 to 13 and Comparative Example 1 were tested according to the following method: 1. Burst resistance: Test the burst resistance of the sample according to the test method specified in GB / T 1539-2007 "Determination of burst resistance of paperboard".

[0043] 2. Far infrared emissivity: Use far infrared emissivity tester to measure the sample.

[0044] The test results are shown in the following table: Table 1 Performance test results of graphene antibacterial paperboards prepared in Examples 1 to 13 and Comparative Example 1 Test Name Burst strength / KPa Far infrared emissivity / % Example 1 536 81 Example 2 542 82 Example 3 551 83 Example 4 557 82 Example 5 589 85 Example 6 598 85 Example 7 604 86 Example 8 601 86 Example 9 594 85 Example 10 629 87 Embodiment 11 638 88 Example 12 623 87 Embodiment 13 616 87 Comparative Example 1 579 80 Compared with Comparative Example 1, Example 2 added L-phenylalaninol. As a result, the bursting strength and far-infrared emissivity of Example 2 were greater than those of Comparative Example 1, indicating that the addition of L-phenylalaninol can significantly improve the strength and antibacterial properties of paperboard.

[0045] Compared with Examples 2 and 4, Examples 5 to 9 simultaneously added the first graphene oxide and the second graphene oxide. As a result, the bursting resistance and far-infrared emissivity of Examples 5 to 9 were greater than those of Examples 2 and 4, indicating that the first graphene oxide and the second graphene oxide played a synergistic role and could further enhance the strength and antibacterial properties of the paperboard.

[0046] Compared with Example 5, Examples 6 to 9 added the first graphene oxide and the second graphene oxide in different mass ratios. As a result, the bursting resistance and far-infrared emissivity of Examples 6 to 8 were greater than those of Examples 5 and 9, indicating that when the mass ratio of the first graphene oxide to the second graphene oxide is 1 to 3:1, and the preferred ratio is 2:1, the strength and antibacterial properties of the obtained paperboard are better.

[0047] Compared with Example 7, Examples 10 to 13 added different mass fractions of L-phenylalaninol. As a result, the bursting strength and far-infrared emissivity of Examples 10 to 12 were greater than those of Examples 7 and 13, indicating that when the mass ratio of L-phenylalaninol to graphene oxide was 3 to 5:1, and the preferred ratio was 4:1, the strength and antibacterial properties of the obtained paperboard were optimal.

[0048] The above are only preferred embodiments of the present invention and are not intended to limit the present invention. Any modifications, equivalent substitutions, improvements, etc. made within the spirit and principles of the present invention should be included in the protection scope of the present invention.

Claims

1. A graphene antibacterial paperboard, characterized in that: The invention comprises the following raw materials in parts by weight: 0.1-0.6 parts of graphene oxide, 0.1-1 parts of polymerized quaternary ammonium salt, 3-8 parts of sizing agent, 0.05-0.1 parts of cationic polyacrylamide, 90-100 parts of wood pulp and 0.2-1.8 parts of L-phenylalaninol.

2. The graphene antibacterial paperboard according to claim 1, characterized in that: The graphene oxide consists of a first graphene oxide and a second graphene oxide, and the first graphene oxide and the second graphene oxide have different oxygen contents.

3. The graphene antibacterial paperboard according to claim 2, characterized in that: The oxygen content of the first graphene oxide is 30 wt %, and the oxygen content of the second graphene oxide is 45 wt %.

4. The graphene antibacterial paperboard according to claim 2, characterized in that: The mass ratio of the first graphene oxide to the second graphene oxide is 1-3:

1.

5. The graphene antibacterial paperboard according to claim 1, characterized in that: The graphene oxide has 3 to 5 layers and a median diameter of less than 1 μm.

6. The graphene antibacterial paperboard according to claim 1, characterized in that: The polymeric quaternary ammonium salt comprises one or both of pharmaceutical grade polydimethyldiallylammonium chloride and pharmaceutical grade polyquaternary ammonium urea-containing polymer.

7. The graphene antibacterial paperboard according to claim 1, characterized in that: The sizing agent includes one or both of modified starch and polyvinyl alcohol.

8. The graphene antibacterial paperboard according to claim 1, characterized in that: The mass ratio of L-phenylalaninol to graphene oxide is 3-5:

1.

9. The method for preparing a graphene antibacterial paperboard according to any one of claims 1 to 8, characterized in that: The following steps are involved: S1, after mixing graphene oxide with water, adding polymerized quaternary ammonium salt, dispersing evenly and drying to obtain surface pretreated graphene oxide; S2, mixing the surface pretreated graphene oxide, cationic polyacrylamide, wood pulp, and L-phenylalaninol uniformly to obtain a slurry; S3, slurry forming, pressing, drying, calendering, single-sided gluing to obtain paperboard.

10. The method for preparing a graphene antibacterial paperboard according to claim 9, characterized in that: The dryness after drying in step S3 is 92-95%.