Polypropylene is a semi-crystalline thermoplastic polymer made from propylene monomers through addition polymerization. It is non-toxic, odorless, light in texture, with a density of 0.89-0.92 g/cm3, which is the density of thermoplastic resin; the melting point is 164-176 ℃, softening at around 155 ℃, and the use temperature range is -30-140 ℃. Polypropylene is light, wear-resistant, antibacterial, easy to dye, insulating, chemically stable, heat-resistant, corrosion-resistant, weather-resistant, and plastic. It is particularly suitable for seawater operations, packaging, water rescue, etc.