Shrinkable film capable of being overlapped and heat sealed, preparation method therefor, and packaging bag prepared using same

An overlapping heat sealable shrink film, including an outer layer and a heat sealing layer, wherein the outer layer contains Polyolefin, Ethylene copolymer, low molecular weight compounds and is after electronically crosslinked treatment, the material of the heat sealing layer is one or more of Polyolefin, Ethylene copolymer and Surlyn, the low molecular weight compounds are selected from one or more of Paraffin, Oleamide, Stearic acid and their derivatives, and the Ethylene copolymer is selected from Ethylene-Vinyl acetate copolymer, Ethylene-Methyl acrylate copolymer, Ethylene-Acrylic acid copolymer and Ethylene-Maleic anhydride copolymer;

• wherein the overlapping heat sealable shrink film contains the following layers from outside to inside:
• outer layer, containing 60 wt % to 95 wt % Polyolefin, 3 wt % to 10 wt % Ethylene copolymer and 2 wt % to 30 wt % low molecular weight compounds;
• intermediate layer, wherein the material is one or more of Vinylidene chloride copolymer, Ethylene vinyl alcohol copolymer, Polyolefin, Ethylene copolymer and Surlyn;
• and
• wherein sealing layer contains 50 wt % to 100 wt % Polyethylene and 0 wt % to 50 wt % Ethylene-vinyl acetate copolymer.