Propylene-based elastomeric composition

A polyolefin elastomeric composition, the composition consisting essentially of:

• (a) a propylene-based elastomer having at least seventy five weight percent (75 wt %) units derived from propylene and from eleven to seventeen weight percent (11-17 wt %) units derived from ethylene, the propylene-based elastomer exhibiting:
• (1) a heat of fusion by DSC analysis of from 2 Joules/gram to 15 Joules/gram;
• (2) a molecular weight distribution (Mw/Mn) of less than 3.5;
• (3) a melt flow rate of from 2 to 30 g/10 minutes;
• and
• (4) substantially isotactic propylene sequences;
• and
• (b) a homogeneous ethylene-alpha olefin interpolymer selected from a substantially linear polyethylene and a homogeneously branched linear polyethylene comprising from 91 to 97 mole percent units derived from ethylene and 3 to 9 mole percent units derived from an alpha olefin having from 4 to 12 carbon atoms and having a density of from 0.890 to 0.910 g/ml, a molecular weight distribution (Mw/Mn) of less than 3.5, an index of refraction from 1.503 to 1.509, and a heat of fusion of from 75 to 115 Joules/gram, wherein the weight ratio of the propylene-based elastomer to the homogeneous ethylene-alpha olefin interpolymer is from 97:3 to 80:20, and wherein the composition has a molecular weight distribution (Mw/Mn) of between 1.7 and 10 and exhibits a heat of fusion from 2 to 55 Joules/gram, a peak crystallization temperature of at least 20° C., and a 2% secant flexural modulus of less than 67 MPa.

A polyolefin elastomeric composition, the composition consisting essentially of:

• (a) a propylene-based elastomer having at least seventy five weight percent (75 wt %) units derived from propylene and from twelve to sixteen weight percent (12-16 wt %) units derived from ethylene, the propylene-based elastomer exhibiting:
• (1) a heat of fusion by DSC analysis of from 2 Joules/gram to 12 Joules/gram;
• (2) a molecular weight distribution (Mw/Mn) of less than 3.5;
• (3) a melt flow rate of from 2 to 30 g/10 minutes;
• and (3) substantially isotactic propylene sequences;
• and
• (b) a homogeneous ethylene-alpha olefin interpolymer selected from a substantially linear polyethylene and a homogeneously branched linear polyethylene comprising from 91 to 97 mole percent units derived from ethylene and 3 to 9 mole percent units derived from an alpha olefin having from 4 to 8 carbon atoms and having a density of from 0.895 to 0.905 g/ml, a molecular weight distribution (Mw/Mn) of less than 3.0, an index of refraction from 1.505 to 1.507, and a heat of fusion of from 89 to 101 Joules/gram, wherein the weight ratio of the propylene-based elastomer to the homogeneous ethylene-alpha olefin interpolymer is from 90:10 to 84:16, and wherein the composition has a molecular weight distribution (Mw/Mn) of between 2.0 and 5.0, exhibits a heat of fusion from 2 to 50 Joules/gram, a peak crystallization temperature of at least 40° C., and a 2% secant flexural modulus of less than 30 MPa.