olypropylene (PP) is a kind of colorless translucent cylindrical particles. The relative density is 0.89-0.91, which is the lightest plastic variety. With chemical resistance, heat resistance, electrical insulation, high strength mechanical properties and good high wear-resistant processing performance, it is widely used in plastic woven products, fiber products, medical materials, automobiles, home appliances, toys, pipes, chemical containers and other production fields.