A terpolymer compositions made from or containing:

A) From 80 wt % to 97 wt %; of a first propylene, ethylene, 1-butene terpolymer having:

i) the content of ethylene derived units ranging from 0.5 wt % to 3.2 wt %;
ii) the content of 1-butene derived units ranging from 7.2 wt % to 14.8 wt %; and


B) From 20 wt % to 3 wt %; of a second propylene, ethylene, 1-butene terpolymer having:

i) the content of ethylene derived units ranging from 0.5 wt % to 3.2 wt %;
ii) the content of 1-butene derived units ranging from 14.4 wt % to 26.5 wt %; and


the terpolymer composition having the melt flow rate, MFR, measured according to ISO 1133 at 230° C. with a load of 2.16 kg, ranging from 3.0 g/10 min to 20.0 g/10 min; the sum of the amounts of A) and B) being 100 wt %.