Polypropylene is a polymer obtained 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°C, and it softens at about 155°C. The operating temperature range is -30~140°C. It is resistant to corrosion by acid, alkali, salt solution and various 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, transportation pipelines, chemical containers, etc., and also used in food and drug packaging.