On food packaging of paper products (2)
food packaging is a major industry in the packaging industry, accounting for about 70% of the packaging industry. Among all kinds of packaging materials, plastic has the characteristics of portability, cheapness and good barrier, and occupies a large share in the food packaging market. However, due to the harmfulness and non degradability of plastic to human health, its further development in the field of food packaging is limited. In recent years, the advantages of paper packaging in the field of food packaging are becoming more and more obvious. Internationally, some countries stipulate that plastic bags are prohibited for packaged food and advocate the use of paper products for green packaging
compared with plastic packaging, paper packaging has many advantages, mainly reflected in:
1 Good hygiene and extensive source of raw materials;
2. Degradability and recyclability;
3. Good temperature tolerance;
4. The unique porous structure makes the paper material have excellent reprocessability;
5. Excellent plasticity;
6. Because the paper material has good affinity for water-soluble glue and water-based ink, the paper packaging is environmentally friendly
in addition, paper and paper products are light, have good stiffness and easy formability, and can be made into food packaging products with different functions and ways. In addition, their outstanding environmental protection makes them more and more widely used in food packaging.
I. paper packaging product molding technology
paper packaging product molding technology can be divided into two categories: one is to copy the pulp suspension on the paper machine (mainly circular shaper, elongater, and pinch shaper) to form sheet paper of different thickness, and then carry out secondary processing, or coating, impregnation, or wrapping plastic molding to make packaging products with various functions and shapes, such as paper bags, paper cups, paper cylinders, oil proof Waterproof products, etc. The second type is the direct dehydration and molding of pulp suspension in a certain shape of mold, which is often referred to as pulp molding technology. The first type of molding method has a long history and mature technology. With the emergence of various new paper processing technologies in recent years, the number and variety of food packaging products using this type of molding method are increasing. This kind of processing technology makes full use of the reprocessability of paper materials. For example, paper has loose and porous structure and good liquid absorption performance. Through the absorption of different liquids, it can have different functions. For example, absorbing oil repellent can be made into oil food packaging paper; Absorbing preservatives can meet the fresh-keeping requirements of fruit and vegetable products through the release of preservatives. Many functions required by food packaging, such as insect prevention and corrosion prevention, have great differences between the test results and the actual values, which can be achieved through this kind of molding technology. Pulp molding technology is a paper product molding technology developed in recent thirty or forty years. It uses the formability of pulp to make paper molded products of arbitrary shape through water filtration and mold design. If additives with certain functions are added to the pulp or different coatings are sprayed on the surface of the molded products after molding, the paper molded products can have many functions, such as waterproof, oil proof, rust proof and so on. This paper product molding technology is mainly used in the packaging field, whether it is the buffer packaging of industrial products or food packaging. New types and new uses of paper mold products made by this forming technology are emerging, and the consumption is also gradually increasing
II. Application of paper products in food packaging
1 Paper food packaging products being used and developed at home and abroad
① paper packaging film: research and develop high-performance paper packaging film to replace the plastic film commonly used in food packaging; ② disposable paper containers instead of plastic: disposable paper containers such as paper cups, paper trays, paper bowls and cartons can replace all kinds of plastic containers, and waste can also be used as secondary fiber in the paper industry, greatly reducing the pollution of plastic waste. ③ development of non wood resources: using other natural resources other than wood to produce paper packaging materials can not only reduce costs, but also save forest resources and protect the ecological environment. China has been able to use straw, wheat straw, flax, bagasse to produce paper packaging products and fast food cartons with good quality.
2. Classification of paper food packaging products
according to different manufacturing processes, paper food packaging products can be divided into the following two categories. ① paper mold food packaging. In paper packaging, pulp molding packaging has shown strong vitality. Compared with paperboard products, pulp molded products have the advantages of better shock resistance, lower cost, recyclability after use, and no pollution to the environment. Therefore, the annual output of pulp molded products in the world has soared at present. In the domestic and foreign markets, pulp molded products are mainly used for the inner packaging of fresh eggs, fruits, alcohol, porcelain, glassware, refined handicrafts and other products. Paper trays and lining parts formed by molds with different cavities have good strength, earthquake resistance, moisture resistance and other properties. It can protect products and keep fresh in storage and transportation.
this kind of food packaging container mainly refers to the pulp molded packaging container with internal sizing, which is made by adding additives to the pulp. Although there are not many kinds of packaging containers for food packaging products made by this method, they have shown good development prospects
paper egg tray: egg tray is the earliest pulp molded product, which has been used in the storage, transportation and sales of fresh eggs. It has excellent cushioning performance and plays a good protective role. At present, the annual output of paper egg saucers is far less than the demand, so it has great development prospects.
paper cans: the production technology of paper cans adopts China's original pulp high-pressure compression molding technology. In fact, its appearance and function are similar to aluminum cans, with less investment, low cost, less pollution and wide applications. The successful research and development of paper cans can be further extended to the packaging field of medicine, chemical industry, paint and other products. With this technology, various paper containers such as high, medium and low-grade cartons, paper bowls, paper cups, paper trays and paper barrels can also be produced. It is predicted that paper cans will be popular in China in a timely manner. With the production development of China's beverage and other industries, their annual demand will reach about 60billion, with broad market prospects and good export potential.
paper disposable milk bottles: Taiwan has developed disposable milk bottles, which are directly made of pulp, and are directly formed by adding additives in the pulp, such as oil-proof, water-proof, heat preservation additives, etc. with the help of molds. They have the characteristics of heat resistance, tension resistance, no leakage, no deformation, and simple assembly. After eating, they do not need to be washed, steamed, disinfected, which is convenient, safe, and environmentally friendly, meeting people's needs and keeping up with the pace of the times. (to be continued)