Patent ID: 8809462

Claim:
An ethylene-α-olefin copolymer comprising monomer units derived from ethylene and monomer units derived from an α-olefin having 3 to 20 carbon atoms, having a density (d) of 860 to 950 kg/m 3 , having a melt flow rate (MFR) of 0.01 to 100 g/10 min, and having a bimodal molecular weight distribution, wherein the elongational viscosity nonlinear index ratio (k1/k2) thereof and the MFR satisfy the following relation: 0.084×ln(MFR)+0.69 <k 1 /k 2<0.126×ln(MFR)+1.03, wherein k1 is a value calculated as a slope of ln α(t) during t=2.0 seconds to 2.5 seconds and k2 is a value calculated as a slope of ln α(t) during t=1.5 seconds to 2.0 seconds, for a curve α(t): α( t )=σ 1 ( t )/σ 0.1 ( t ) wherein the curve α(t) is obtained by dividing a viscosity-time curve σ 1 (t) of a melted resin when monoaxially elongated at a temperature of 130° C. and a strain rate of 1 s −1 at Hencky strain by a viscosity-time curve σ 0.1 (t) of a melted resin when monoaxially elongated at a temperature of 130° C. and a strain rate of 0.1 s −1 at Hencky strain.