Propylene-based composition for pipes

A polyolefin composition comprising:

• A) from 85.0 wt % to 99.5 wt % of a propylene 1-hexene copolymer based upon the weight of the polyolefin composition, wherein:
• (i) the content of 1-hexene derived units ranges from 0.6 1.0 wt % to 6.0%, based upon the weight of the propylene 1-hexene copolymer;
• ii) the melt flow rate (MFR) (ISO 1133 230° C., 5 kg) ranges from 0.6 to 5.0 g/10 min;
• iii) the xylene soluble content measured at 25° C. lower than 10 wt %, based upon the weight of the propylene 1-hexene copolymer;
• and
• B) from 0.5 wt % to 15.0 wt % of a propylene, ethylene copolymer composition, based upon the weight of the polyolefin composition, comprising:
• b1) from 12 wt % to 52 wt %, based upon the weight of the propylene, ethylene copolymer composition, of a propylene homopolymer or a propylene/ethylene copolymer having a content of ethylene derived units ranging from 0.1 wt % to 4.5 wt %, based upon the weight of the propylene/ethylene copolymer;
• and having a xylene soluble content measured at 25° C. lower than 10 wt %, based upon the weight of the propylene homopolymer or the propylene/ethylene copolymer;
• and
• b2) from 48 wt % to 88 wt %, based upon the weight of the propylene, ethylene copolymer composition, of a propylene ethylene copolymer having a content of ethylene derived units ranging from 15.0 wt % to 42.0 wt %, based upon the weight of the propylene ethylene copolymer;
• wherein the polyolefin composition has a melt flow rate (230° C./5 kg. ISO 1133) ranging from 0.2 g/10 min to 4.0 g/10 min;
• the sum A+B being 100;
• the sum b1+b2 being 100;
• and the copolymers having only two type of monomers.