Patent ID: 7449522

Claim:
A process for making a blown film comprising: blending at least one broad molecular weight distribution ethylene/propylene rubber impact-modified heterophasic copolymer (ICP), wherein the ICP has a polydispersity from about 4 to about 12, a melt flow rate from about 0.5 to about 5.0 dg/min and xylene solubles of about 25% or less, with from about 5 to about 95 wt % of at least one second polyolefin, where the second polyolefin is selected from the group consisting of a syndiotactic polypropylene (sPP), a medium density polyethylene (MDPE), a linear low density polyethylene (LLDPE), a low crystalline copolymer of propylene/α-olefin, and a random copolymer (RCP) of propylene and comonomer selected from the group consisting of ethylene and butenes, where the RCP is made using a Ziegler-Natta or metallocene catalyst; feeding the polymer blend to an extruder; extruding the polymer blend through an annular die to form a molten tube; and blowing the tube into a bubble using air to form a blown film structure.