HEAVY DUTY PACKING BAG

PROBLEM TO BE SOLVED: To provide a heavy duty packing bag that excels in heat seal, transparency, surface gloss, and printability, has a high product appeal in a condition where the bags are stacked, and can be used suitable for a packing bag for heavy objects, such as rice grains, fertilizers, etc. SOLUTION: The heavy duty packing bag is constituted with a laminated film formed by coexttrusion of polyethylene and polypropylene, and the polyethylene forming an inner layer of the laminated film is polymerized by a metallocene catalyst. The polypropylene forming an outer layer of the laminated film is random polymerized by a metallocene catalyst. 5 to 50 wt.% of polyethylene polymerized by the metallocene catalyst (L-LDPE) is mixed with the polypropylene forming the outer layer. An intermediate layer made of polyethylene is intervened between the outer layer and the inner layer. A ratio of thicknesses of the outer layer, the intermediate layer, and the inner layer is 1:1-4:1-3. The inner layer of the laminated film is positioned on an inner surface thereof, and the outer layer is positioned on an outer surface to form the bag by envelop-like paste. COPYRIGHT: (C)2009,JPO&INPIT