A process for the preparation of a heat sealable film comprising a core layer and a sealing layer, said process comprising attaching said core layer to said sealing layer, said sealing layer comprising an ethylene copolymer composition in which: (1) there are two distinct maxima in the TREF fractogram of the ethylene copolymer composition; (2) at lest 10%, of the ethylene copolymer composition elutes in TREF at a temperature of less than 50 C.; (3) at least 25%, of the ethylene copolymer composition elutes in TREF at a temperature of higher than 75 C.; (4) none of the ethylene copolymer composition elutes in TREF at a temperature of higher than 100 C.; (5) the ethylene copolymer composition comprises two components, one of which is of relatively high comonomer content and high molecular weight, the other of which is of relatively low comonomer content and low molecular weight, both components being prepared by polymerisation of ethylene with a C_3-20 alpha-olefin in the present of a single site catalyst; (6) the ethylene copolymer composition has a density of between 905 and 930 kg/m³, and an MFR₂ between 0.3 and 4.0 g/10 min.