Composition comprising propylene-ethylene-1-butene terpolymers

A film comprising:

• (i) a polyolefin composition comprising:
• A) from about 19 wt % to about 50 wt %, based upon the total weight of the polyolefin composition, of a propylene ethylene copolymer having an ethylene derived units content ranging from about 1.5 wt % to about 6.0 wt %, based upon the total weight of the propylene ethylene copolymer;
• B) from about 50 wt % to about 81 wt %, based upon the total weight of the polyolefin composition, of a propylene ethylene 1-butene terpolymer having an ethylene derived units content ranging from about 1.5 wt % and about 6.0 wt %, based upon the total weight of the propylene ethylene 1-butene terpolymer, and 1-butene derived units content of between about 4.8 wt % and about 12.4 wt %, based upon the total weight of the propylene ethylene 1-butene terpolymer;
• the sum of the amount of component A) and B) being 100;
• the polyolefin composition being characterized by the following features:
• molecular weight distribution (MWD), expressed in terms of Mw/Mn, greater than about 4.0;
• the creep and recovery curve measured on the polymer fuse at 200° C. shows a maximum value between 600 and 1200 seconds, lower than about 53×10−5 1/Pa.

A polyolefin composition comprising:

• A) from about 19 wt % to about 50 wt %, based upon the total weight of the polyolefin composition, of a propylene ethylene copolymer having an ethylene derived units content ranging from about 1.5 wt % to about 6.0 wt %, based upon the total weight of the propylene ethylene copolymer and
• B) from about 50 wt % to about 81 wt %, based upon the total weight of the polyolefin composition, of a propylene ethylene 1-butene terpolymer having an ethylene derived units content ranging from about 1.5 wt % to about 6.0 wt %, based upon the total weight of the propylene ethylene 1-butene terpolymer, and 1-butene derived units content of between about 4.8 wt % and about 12.4 wt %, based upon the total weight of the propylene ethylene 1-butene terpolymer;
• the sum of the amount of component A) and B) being 100 wt. %, based on the total weight of the polyolefin composition;
• wherein the polyolefin composition being characterized by the following features:
• a molecular weight distribution (MWD), expressed in terms of Mw/Mn, greater than about 4.0;
• a creep and recovery curve measured on a polymer fuse at 200° C. shows a maximum value between 600 and 1200 seconds, lower than about 53×10−5 1/Pa;
• wherein the polyolefin composition is prepared by a process including:
• (i) forming the propylene ethylene copolymer by polymerizing propylene with ethylene in a first stage,
• (ii) forming the propylene ethylene 1-butene terpolymer by polymerizing propylene, ethylene and 1-butene in a second stage in the presence of a catalyst made containing the product of the reaction between:
• (a) a solid catalyst component containing Ti, Mg, Cl and an electron donor compound containing from about 0.1 to about 50 wt. %, based on the total weight of the solid catalyst component, of Bi,
• (b) an alkylaluminium compound, and
• (c) an external electron-donor compound.