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Research and development prospects of bagasse cushioning packaging materials

Abstract: This paper summarizes the performance and development prospects of bagasse fiber cushioning packaging materials, and theoretically analyzes its foaming technology, pointing out that this green packaging material is an ideal substitute for plastic foaming packaging materials. Carrying out this research is of great significance to protect the environment and save energy

key words: bagasse fiber; Cushioning packaging materials; Foaming methods

1 preface

with the rapid development of industry, there is an increasing demand for packaging materials, especially foam polystyrene (EPS), a packaging material with cushioning properties. EPS has been used in the packaging of household appliances, electronic instruments, glassware and other products. However, due to the long-term non biodegradable waste of plastic foaming materials in nature, which has caused serious "white pollution" to the environment, it has been banned by many countries and will be gradually banned in China. At present, the alternative product of EPS is pulp molded shockproof lining products, which is made of waste newspapers, carton paper and other plant fibers as the main raw materials, through hydraulic machinery pulping, mold vacuum adsorption molding, and then drying. The shock resistance and impact resistance of such products are mainly guaranteed by the geometric structure of the products. Due to the influence of mold structure and processing, the products are greatly restricted. Only the packaging liners of small household electrical appliances can be made, while the packaging liners and filling of large household electrical appliances still use EPS foam products. At the same time, the cost of pulp molding is higher than that of EPS foam products, Therefore, it also greatly limits the development of pulp molded products. In recent years, a new type of packaging material - plant fiber foaming packaging products and its molding technology are under research and development. This product is made of plant fiber through foaming, adding starch adhesive additives and other materials. Since the main raw materials are bagasse, wheat straw, straw and other fiber materials as well as industrial starch, they will not cause obstacles to the environment and recycling, and can be reused, recycled and naturally degraded. The development and application of green cushioning packaging materials has become an inevitable trend in the 21st century. Therefore, it is of great significance to carry out the research on using new green packaging materials to replace foam cushioning materials

at present, whether at home or abroad, the research on plant fiber cushioning packaging materials is basically in the laboratory stage, and has not reached the requirements of industrialized large-scale continuous production. Bagasse is an inexhaustible renewable resource with concentrated sources and large output in Guangxi. Therefore, the research on developing cushioning packaging materials with bagasse as raw material through crushing, foaming, molding and other processes has opened up a broader prospect for the rational utilization of bagasse

2 performance characteristics of bagasse fiber cushioning packaging material

using bagasse as cushioning packaging material is a new environmental protection packaging material and an excellent substitute for plastic foam packaging material. The new packaging material, like other plant fiber foaming packaging products, has the following performance characteristics: (1) the main raw materials of plant fiber foaming packaging products are waste paper (bagasse, wheat straw, straw, etc.) and industrial starch, which will not cause obstacles to the environment and recycling, and is conducive to the product export of manufacturers. (2) ) plant fiber foaming packaging products have a wide range of applications. With the progress of plant fiber foaming technology, products that use EPS foam as lining and filling packaging can be replaced. (3) ) low comprehensive cost. Compared with pulp molding products, plant fiber foaming products have simple process, no need for complex molding and hot pressing mold, short production time and cycle, low energy consumption and raw material cost. (4) The anti-static and anti-corrosion properties are better than EPS foamed materials, and the anti vibration and isolation properties are better than pulp molded products, which is basically equivalent to the cushioning properties of foamed plastic products, without the cushioning formed by the mechanical structure of paper molded products through their complex geometric shapes, which reduces the manufacturing difficulty of products. (5) In force value detection, shock absorption and shock resistance are better than pulp molded products. According to the requirements of different packaged products, a variety of auxiliary additives such as strengthening agent, flexibility agent, waterproof agent, oil proof agent, flame retardant can be added to achieve a variety of functions. (6) It can be used to make packaging liners and fillers for large household appliances and electronic products, and can fill the gap of pulp molded products that have not been able to make such packaging products so far [1]

3 theoretical basis for the development of bagasse fiber buffer packaging materials

the main chemical composition of bagasse is similar to that of wood, which is composed of cellulose, wood tear at the right angle of the sample, hemicellulose and other parts. The experimental formula of cellulose is C6H10O5. There are three free hydroxyl Oh at the 2, 3 and 6 positions of its macromolecule, a microfibril is composed of 300~500 glucose groups, and the fiber bundle contains a large number of microfibrils, The active hydroxyl group at the end of the fiber bundle can be exposed more by "brooming" [2]. The interaction of secondary bond forces (hydrogen bond force, van der Waals force) between active groups on different fibers can bridge the interconnection of fibers. The ideal structure of plant fiber foam material should be a three-dimensional structure, and the strength of this structure depends on the strength of the fiber bundle itself and the connection strength between the fiber bundles. In order to ensure the realization of this structure, the discrete fibers should be framed into a shaped structure under the action of a certain medium, and the fibers should be connected with each other. When the medium is removed, the desired plant fiber foam material should be formed. The foaming technology of bagasse fiber foaming products is the key technology of the project. According to the existing technical conditions, there are mainly two foaming processes: using chemical foaming agent and not using chemical foaming agent. At present, the methods used in Europe, America, Japan and other countries mainly focus on the process of not adding chemical foaming agent. The raw materials are foamed through the action of steam, which causes some users to complain that the instrument has problems, forming granular foamed pulp. This production is more difficult than the process of adding chemical foaming agent, but the production and use do not pollute the environment. There are also several institutions and units in China that are carrying out research and development of this technology. The process method of plant fiber foaming products researched and developed mainly focuses on adding chemical foaming agent, and the raw materials are foamed through the action of chemical foaming agent to form granular foaming pulp. The process using foaming agent is simpler than that without foaming agent. However, if the foaming agent is improperly selected, the foaming method and products of this kind of plant fiber may have an impact on the environment during the production process and post-use treatment, which may cause some areas that do not receive excess capacity to transfer capacity, so this technology needs to be improved and improved. On the basis of synthesizing the unity of the current domestic and foreign research on the foaming technology of plant fibers, the secondary foaming combined with mechanical and chemical methods is used to promote and control the formation of bubbles. A certain amount of water is added to the bagasse fiber to form a high concentration of fiber slurry. While mechanical stirring, a small amount of gas is introduced to form a small gas core dissolved in the slurry, and then chemical foaming agent, adhesive and foam stabilizer are added, Because the tiny bubbles formed in the first foaming process become the bubble core of the second foaming, it promotes the rapid generation of bubbles and increases the fineness of bubbles at the same time. When the foaming process is stable and the stirring is over, the fiber forms a "three-dimensional" under the action of the jacking force and secondary bond force of the bubble [3]. Secondary foaming can better promote and control the formation of bubbles to improve the stability of materials. Send the foamed slurry into the special metal mold, pressurize and heat it in the metal mold, and produce packaging materials with different shapes corresponding to the metal mold in terms of manufacturing accuracy and wall thickness

4 the development prospect of bagasse fiber cushioning packaging materials

bagasse is very abundant in Guangxi, with an annual output of hundreds of millions of tons. In addition to being used for papermaking, many have not been fully utilized. At present, bagasse based fast-food lunch boxes have come out, which can replace disposable foamed plastic fast-food boxes, but foamed plastic has been used as the packaging material for household appliances, electronic instruments, glassware and other products, In particular, the largest amount of foam PS is used. These materials are one of the major sources of white pollution. With the rapid development of the household appliance market, white pollution caused by packaging materials is becoming more and more serious. In order to truly eliminate white pollution, in addition to prohibiting disposable foamed plastic fast-food boxes, we must also eliminate foamed plastic inner packaging materials as soon as possible and replace them with degradable green cushioning packaging materials. At this point, you should also pay special attention to the development of green packaging materials with bagasse as raw material, which is of far-reaching significance for improving the packaging of mechanical and electrical products, saving energy and protecting the environment, and is of great significance for mechanical and electrical products to be in line with international standards and further expand mechanical and electrical products, which is in line with the development trend of international packaging. Therefore, the use of bagasse green cushioning packaging materials can not only reduce costs, protect the environment and alleviate natural resources, but also make a significant contribution to increasing export competitiveness

Zou Jun, Li Qingchun, Dong Xianxin (Guangxi chemical fiber research institute

author profile: Zou Jun, female, engineer, bachelor degree, major in polymer materials, now works in the scientific research and Development Office of Guangxi chemical fiber research institute, engaged in the research and development of polymer materials.

reprinted from: light industry scientific and technological papers