A sealant resin composition comprises 60 to 95 weight percent of ethylene polymer (PE) and 5 to 40 weight percent of 1-butene polymer (PB), wherein a melt flow rate (MFR) ratio between the two polymers (MFRPE/MFRPB) is not less than 1. A laminated film obtained by extrusion laminating the resin composition as a sealant film layer over a substrate film adheres tightly to other plastic film by heat sealing and gives a low degree of dependence of heat seal strength on temperature in the heat sealing stage. At the same time the laminated film has an easy peel feature, such that it is readily separated from sealed surfaces after heat sealing, and does not develop any phenomenon of resin threading from the sealed surfaces when they are peeled apart. Accordingly the resin composition is suitably used for the food packaging material. |