Propylene polymers having broad molecular weight distribution

摘要

Propylene homopolymers or copolymers containing up to 5.0 wt % of alpha-olefin units having from 2 to 8 carbon atoms other than propylene, characterized in that said propylene homopolymers or copolymers have Polydispersity Index value higher than 15, Melt Strength higher than 1.50 cN at 230° C. and Melt Flow Rate (ISO1133, 230° C./2.16 Kg) from 0.01 to 20 g/10 min.

主权项

1. A propylene copolymer comprising:
(i) 0.5 to 5 wt. %, based on the total weight of the copolymer, of ethylene derived units; and (ii) 95 to 99.5 wt. %, based on the total weight of the copolymer, of propylene derived units, wherein the copolymer has; a Polydispersity Index value from 20 to 35; a Melt Strength higher than 1.50 cN at 230° C.; a Flexural Modulus (ISO178) from 1500 to 2000 MPa; a number of gels No(≧0.2 mm) of less than 400; and a Melt Flow Rate (ISO1133, 230° C./2.16 Kg) from 0.5 to less than 1.7 g/10 min, wherein the propylene copolymer is produced in a single polymerization step by feeding the monomers and the catalyst system to a gas-phase polymerization reactor comprising two interconnected polymerization zones.