A polymer composition comprising: A) from 70 wt% to 95 wt% of a propylene composition comprising: A1) from 19 wt% to 50 wt% of a propylene ethylene copolymer having an ethylene derived units content ranging from 1.5 wt% to 6.0 wt%; A2) from 50 wt% to 81 wt% of a propylene ethylene 1-butene terpolymer having an ethylene derived units content ranging from 1.5 wt% and 6.0 wt% and 1-butene derived units content of between 4.8 wt% and 12.4 wt%; the sum of the amount of component A1) and A2) being 100; the composition being characterized by a xylene soluble fraction at 0/25 °C comprised between 2 wt% and 15 wt%; the sum of the amounts of A1) and A2) being 100 wt%; B) from 5.0 wt% to 30.0 wt% of a copolymer of 1-butene and ethylene containing from 3.0 wt% to 4.2 wt% of ethylene derived units; said copolymer of 1-butene and ethylene having: - a Melt Flow Rate: measured according to ISO 1133-1 -(190 °C, 2.16 Kg) ranging from 1.0 to 5.5 g/10 min; flexural modulus measured according to ISO 178 ranging from 80 MPa to 250 MPa; the melting temperature measured according to Iso 11357-2013 ranging from 83°C and 108 °C, form I. the sum of the amounts of A) and B) being 100 wt%. A) from 70 wt% to 95 wt% of a propylene composition comprising: A1) from 19 wt% to 50 wt% of a propylene ethylene copolymer having an ethylene derived units content ranging from 1.5 wt% to 6.0 wt%; A2) from 50 wt% to 81 wt% of a propylene ethylene 1-butene terpolymer having an ethylene derived units content ranging from 1.5 wt% and 6.0 wt% and 1-butene derived units content of between 4.8 wt% and 12.4 wt%; the sum of the amount of component A1) and A2) being 100; the composition being characterized by a xylene soluble fraction at 0/25 °C comprised between 2 wt% and 15 wt%; the sum of the amounts of A1) and A2) being 100 wt%; A1) from 19 wt% to 50 wt% of a propylene ethylene copolymer having an ethylene derived units content ranging from 1.5 wt% to 6.0 wt%; A2) from 50 wt% to 81 wt% of a propylene ethylene 1-butene terpolymer having an ethylene derived units content ranging from 1.5 wt% and 6.0 wt% and 1-butene derived units content of between 4.8 wt% and 12.4 wt%; the sum of the amount of component A1) and A2) being 100; the composition being characterized by a xylene soluble fraction at 0/25 °C comprised between 2 wt% and 15 wt%; the sum of the amounts of A1) and A2) being 100 wt%; the sum of the amount of component A1) and A2) being 100; the composition being characterized by a xylene soluble fraction at 0/25 °C comprised between 2 wt% and 15 wt%; the sum of the amounts of A1) and A2) being 100 wt%; B) from 5.0 wt% to 30.0 wt% of a copolymer of 1-butene and ethylene containing from 3.0 wt% to 4.2 wt% of ethylene derived units; said copolymer of 1-butene and ethylene having: - a Melt Flow Rate: measured according to ISO 1133-1 -(190 °C, 2.16 Kg) ranging from 1.0 to 5.5 g/10 min; - a Melt Flow Rate: measured according to ISO 1133-1 -(190 °C, 2.16 Kg) ranging from 1.0 to 5.5 g/10 min; flexural modulus measured according to ISO 178 ranging from 80 MPa to 250 MPa; the melting temperature measured according to Iso 11357-2013 ranging from 83°C and 108 °C, form I. the sum of the amounts of A) and B) being 100 wt%.