▎ 摘　　要

NOVELTY - Packaging material comprises 80-100 pts. wt. polypropylene particles, 4-6 pts. wt. modified nano-graphene, 1-3 pts. wt. sodium sorbate, 15-20 pts. wt. nano-silver oxide and 0.3-0.5 pt. wt. diethyl phthalate, where the modified nano-graphene is obtained by coating and modifying chitosan sol. USE - The packaging material is useful for forming packaging bag used for extending shelf life of steamed buns. ADVANTAGE - The packaging material has water vapor transmission rate, oxygen transmission rate, tensile strength and elongation at break of 2.25 g/m2, 2.46 m2/0.1 Mpa, 10.5 MPa and 98%, and the antibacterial rates of the packaging materials against Staphylococcus aureus and Escherichia coliare 95% and 94%, and improves the anti-mold and antibacterial properties, and the steamed buns packaged in the packaging bag has a maximum shelf life of 5 days at 23℃, which effectively prolongs the shelf life of the steamed buns. DETAILED DESCRIPTION - INDEPENDENT CLAIMS are included for: A method for preparing the packaging material, involving melting the polypropylene particles, adding the other raw materials, mixing, extruding to granulate, blowing into a film, and cooling to obtain the packaging material. A packaging bag made from the packaging material.