Plastics are a class of high-molecular organic compounds, a general term for thermoplastic molding materials processed through filling, plasticizing, coloring and other processes, and belong to a family of high-molecular organic polymers. Common plastic materials mainly include: expandable polystyrene (EPS), low-density polyethylene (LDPE), high-density polyethylene (HDPE), polyethylene (PE), polyesters (PET) and polypropylene (PP), etc.