At present, metal can packaging is recognized as a "safer and environmentally friendly product" all over the world. The reason is that the tinplate used in the metal can packaging has good impermeability and light tightness, which can effectively prevent the contents from being oxidized by light and prevent the invasion of pollutants. Therefore, it has the characteristics of safety, hygiene and health. In addition, the more important point is that tin cans are environmentally friendly containers, because they can also be recycled and reused, which is in line with the call of environmental protection advocated by the state. Moreover, if the empty tank is placed in the natural environment, after 7 years of wind and rain, it will naturally oxidize, crush or integrate into the soil.