Cast polypropylene membrane

A cast polypropylene (CPP) membrane is formed by performing three-layer co-extrusion by a casting machine, and possesses a three-layer structure comprising an outer layer, a middle layer and an internal layer. The internal-layer material is formed by blending 50% by weight of terpolymerization polypropylene, 40% by weight of allyl elastomer and 10% by weight of vinyl-vinyl acetate copolymer. The middle-layer material is formed by blending allyl elastomer and metallocene polyethylene, wherein allyl elastomer accounts for 60%-90% by weight. The outer-layer material employs homopolymerization polypropylene or random copolymerization polypropylene resin. The fusion index of all of the above resin is 3-8, the inner-layer thickness is 10 mu m or more, the cast polypropylene membrane is formed through three-layer co-extrusion casting equipment and forms a composite packaging membrane. The airtightness, and toughening and compatibility technical problems of a conventional CPP material are solved. The modified atmosphere packaging high airtightness and high-speed pillow-type automatic packaging (HFFS) requirements are satisfied, and the membrane is especially suitable for baking foodstuff inflation pressure-resistant packaging.