Narrow MWD, compositionally optimized ethylene interpolymer composition, process for making the same and article made therefrom

A polymer composition comprising ethylene interpolymerized with at least one unsaturated comonomer, wherein the composition is characterized as having:

• a) a Mw/Mn of less than or equal to 3.3, as determined by gel permeation chromatography (GPC),
• b) an I10/I2 in the range of from greater than 6.6 to about 8.2, as determined in accordance ASTM D-1238, Condition 190° C./2.16 kg and Condition 190° C./10 kg,
• c) a composition density less than 0.945 gram/cubic centimeter, as defined according to ASTM-792,
• d) at least two polymer components, the first component having a first viscosity average molecular weight, Mv1, and the second component having a second viscosity average molecular, Mv2, wherein Mv1/Mv2 is less than or equal to 1, as determined using ATREF-DV, and
• e) a first ATREF peak temperature, Tpeak1 and a second ATREF peak temperature, Tpeak2, corresponding to the at least two components and as determined using analytical temperature rising elution fraction (ATREF), wherein the temperature differential between Tpeak2 and Tpeak1, ΔT, decreases with increased composition density such that ΔT is less than 23° C. at composition densities of greater than or equal to 0.926 g/cm3, greater than 23° C. at composition densities less than or equal to 0.92 g/cm3, and in the range of from about 10 to about 22° C. at composition densities from about 0.92 to about 0.926 g/cm3,
• wherein the first component polymer is a substantially linear ethylene interpolymer characterized as having:
• i. melt flow ratio, I10/I2≧5.63, and
• ii. a gas extrusion rheology such that the critical shear rate at onset of surface melt fracture for the substantially linear ethylene polymer is at least 50 percent greater than the critical shear rate at the onset of surface melt fracture for a linear ethylene polymer, wherein the substantially linear ethylene polymer and the linear ethylene polymer comprise the same comonomer or comonomers, the linear ethylene polymer has an I2 and Mw/Mn within ten percent of the substantially linear ethylene polymer and wherein the respective critical shear rates of the substantially linear ethylene polymer and the linear ethylene polymer are measured at the same melt temperature using a gas extrusion rheometer.