This standard specifies the product specifications, technical requirements, test methods, inspection rules and requirements for marking, Encasement, transportation and storage of polyolefin thermal cissing films. It is applicable to films with PP/LLDPE/PP structure produced by copolymerized polypropylene (PP) (PP) and linear low-Density polyethylene (PE) (LLDPE) as the main raw materials and using a three-layer co-extrusion process. The standard covers the specific requirements of film width, Film thickness deviation, number of joints, etc., to ensure the mass and conformity of the product in the application, and is widely used in the field of Encasement.