Polypropylene is a polymer formed by addition polymerization of propylene. It is a white waxy material with a transparent and light appearance. The chemical formula is (C3H6)n, the density is 0.89~0.91g/cm3, it is flammable, the melting point is 189℃, it softens at about 155℃, and the use temperature range is -30~140℃. It is resistant to corrosion by acids, alkalis, salt solutions and a variety of organic solvents below 80°C, and can be decomposed under high temperature and oxidation. Polypropylene is widely used in the production of clothing, blankets and other fiber products, medical equipment, automobiles, bicycles, parts, pipelines, chemical containers, etc. It is also used in food and pharmaceutical packaging.