With the improvement of China's economic construction and people's living standards, a variety of packaging materials are increasingly used in a variety of merchandise. Taking beverage soft packaging as an example, a small paper bag has three layers of polyethylene (PE) film, one layer of aluminum foil, and one layer of paper except for ink. It consists of five layers of materials. Although this complex structure makes the packaging material more attractive and durable, it is not easy to damage, but it also brings serious environmental problems:

1 This type of packaging material is coated with several layers of PE film and cannot be degraded after being discarded;

2 The presence of aluminum foil in the composite layer increases the difficulty of incineration;

3 The presence of PE film and ink in the composite layer generates a large amount of harmful gases when incinerated;

4 In the composite layer, plastic, metal, and paper are pressed into a single body, making it difficult to separate the plastic, metal, and paper one by one using a common waste plastic separation method, which presents difficulties for secondary recycling.

In recent years, a variety of domestic packaging materials manufacturers have sprung up. At the same time, some foreign companies such as the United States International Paper, Germany's Pickel and Sweden's Tetra have also entered the packaging material market in China to produce similar products. . Obviously, if the waste of these materials is not considered for proper secondary recycling and comprehensive utilization, over time, it will cause great pollution to our environment. According to the composition features of these waste plastic packaging materials, we designed two recycling comprehensive utilization process routes.

(1) Hot pressing into building boards. The chemical environmental protection process route is: crushing→cleaning→drying→secondary crushing→stirring and adding necessary additives→pressing hot pressing→molding→trimming into products. The advantage of this method is that the amount of additives needed is small. According to the user's requirements for the final quality of the board, building boards with good aging resistance can be obtained by adding antioxidants and light stabilizers, and flame retardant boards can also be obtained by adding flame retardants. The final product has a smooth surface. The disadvantage of this method is that it consumes a lot of energy. Because both plastic and paper are poor conductors of heat, they cause a long hot pressing time and uneven heat inside and outside the plate. When the pressed plate is thick, the surface plate may be coked and the inner layer may not reach the temperature required by the process. Also, it takes a long time to cool and cool the mold release, resulting in a low labor productivity.

(2) The process route of cold pressing into building boards is: crushing→cleaning→drying→secondary crushing→stirring and adding necessary additives→cold pressing of stamping mold→molding→trimming into products. The advantages of this method are low energy consumption, high labor productivity, and a good production environment for workers. The disadvantage of this method is that the consumption of auxiliaries is large, leading to an increase in the cost of raw materials.