The main characteristics of plastics are: First, the density is small, the specific strength is higher, and the higher packaging yield can be obtained, ie, the packaging volume or packaging area of unit mass. Second, most plastics have good chemical resistance. Good acid and alkali resistance, resistance to various types of organic solvents, long-term storage, no oxidation, thirdly, easy molding, less energy to be formed than steel and other metal materials, fourth, good transparency, easy colorability Fifth, it has good strength, high strength per unit weight, impact resistance and easy modification, sixth, low processing cost, and seventh, excellent insulation.