Patent ID: 8106139

Claim:
A composition comprising at least one propylene/ethylene block interpolymer comprising two or more substantially homogeneous intramolecular blocks comprising differing chemical or physical properties and having a difference in mole percent ethylene content, said intramolecular blocks characterized by possessing a most probable molecular weight distribution, wherein the propylene/ethylene block interpolymer is characterized by a molecular weight distribution, M w /M n , in the range of from about 1.4 to about 2.8 and by an average block index greater than zero and up to about 1.0; wherein the propylene/ethylene block interpolymer is mesophase separated; and, wherein the difference in mole percent ethylene content between the intramolecular blocks, Δ(percent comonomer), is calculated according to the following equation: Δ(percent comonomer)≧ A /( Mn ) 0.5 wherein Mn is the number average molecular weight of all molecules in units of g/mole and A is greater than or equal to about 9187.