Polypropylene (PP for short) is a colorless, odorless, non-toxic, translucent solid substance. Polypropylene is a thermoplastic synthetic resin with excellent performance. It has chemical resistance, heat resistance, electrical insulation, high-strength mechanical properties and good high wear-resistant processing performance, etc. Polypropylene has been widely developed and applied in many fields such as machinery, automobiles, electronic appliances, construction, textiles, packaging, agriculture, forestry, fishery and food industry since its inception.