A polyethylene composition comprising: A) 30 - 70% by weight of an ethylene homopolymer or copolymer with density equal to or greater than 0.960 g/cm 3 and melt flow index MIE at 190°C with a load of 2.16 kg, according to ISO 1133, of 2 to 20 g/10 min.; B) 30 - 70% by weight of an ethylene copolymer having a MIE value lower than the MIE value of A), said composition having the following features: 1) density from 0.940 to 0.955 g/cm 3, determined according to ISO 1183 at 23°C; 2) ratio MIF/MIP from 12 to 40, where MIF is the melt flow index at 190°C with a load of 21.60 kg, and MIP is the melt flow index at 190°C with a load of 5 kg, both determined according to ISO 1133-1; 3) Mz from 500,000 to 3,500,000 g/mol, where Mz is the z-average molecular weight, measured by GPC; 4) η 0.02 from 80,000 to 300,000 Pa.s, wherein η 0.02 is the complex shear viscosity at an angular frequency of 0.02 rad/s, measured with dynamic oscillatory shear in a plate-plate rotational rheometer at a temperature of 190°C; 5) HMWcopo index from 1 to 15; wherein the HMWcopo index is determined according to the following formula: HMWcopo = η 0.02 × t maxDSC / 10 ∧ 5 where η 0.02 is the complex shear viscosity of the melt in Pa.s, measured at a temperature of 190°C, in a parallel-plate rheometer under dynamic oscillatory shear mode with an applied angular frequency of 0.02 rad/s; the t maxDSC is the time, in minutes, required to reach the maximum value of heat flow of crystallization at a temperature of 124 °C under quiescent conditions, measured in isothermal mode in a differential scanning calorimetry apparatus; 6) Mz/Mw ∗ LCBI lower than 6.4, wherein LCBI is the ratio of the measured mean-square radius of gyration Rg, measured by GPC-MALLS, to the mean-square radius of gyration for a linear PE having the same molecular weight at a mol. weight of 1,000,000 g/mol. A) 30 - 70% by weight of an ethylene homopolymer or copolymer with density equal to or greater than 0.960 g/cm 3 and melt flow index MIE at 190°C with a load of 2.16 kg, according to ISO 1133, of 2 to 20 g/10 min.; B) 30 - 70% by weight of an ethylene copolymer having a MIE value lower than the MIE value of A), 1) density from 0.940 to 0.955 g/cm 3, determined according to ISO 1183 at 23°C; 2) ratio MIF/MIP from 12 to 40, where MIF is the melt flow index at 190°C with a load of 21.60 kg, and MIP is the melt flow index at 190°C with a load of 5 kg, both determined according to ISO 1133-1; 3) Mz from 500,000 to 3,500,000 g/mol, where Mz is the z-average molecular weight, measured by GPC; 4) η 0.02 from 80,000 to 300,000 Pa.s, wherein η 0.02 is the complex shear viscosity at an angular frequency of 0.02 rad/s, measured with dynamic oscillatory shear in a plate-plate rotational rheometer at a temperature of 190°C; 5) HMWcopo index from 1 to 15; wherein the HMWcopo index is determined according to the following formula: HMWcopo = η 0.02 × t maxDSC / 10 ∧ 5 where η 0.02 is the complex shear viscosity of the melt in Pa.s, measured at a temperature of 190°C, in a parallel-plate rheometer under dynamic oscillatory shear mode with an applied angular frequency of 0.02 rad/s; the t maxDSC is the time, in minutes, required to reach the maximum value of heat flow of crystallization at a temperature of 124 °C under quiescent conditions, measured in isothermal mode in a differential scanning calorimetry apparatus; wherein the HMWcopo index is determined according to the following formula: HMWcopo = η 0.02 × t maxDSC / 10 ∧ 5 where η 0.02 is the complex shear viscosity of the melt in Pa.s, measured at a temperature of 190°C, in a parallel-plate rheometer under dynamic oscillatory shear mode with an applied angular frequency of 0.02 rad/s; the t maxDSC is the time, in minutes, required to reach the maximum value of heat flow of crystallization at a temperature of 124 °C under quiescent conditions, measured in isothermal mode in a differential scanning calorimetry apparatus; 6) Mz/Mw ∗ LCBI lower than 6.4, wherein LCBI is the ratio of the measured mean-square radius of gyration Rg, measured by GPC-MALLS, to the mean-square radius of gyration for a linear PE having the same molecular weight at a mol. weight of 1,000,000 g/mol.