abstract |
A polyethylene composition comprises a first polyethylene which is an ethylene copolymer having a weight average molecular weight of from 70,000 to 250,000 and a molecular weight distribution Mw/Mn of < 2.3, a second polyethylene which is an ethylene copolymer or homopolymer having a weight average molecular weight of less than 75,000 and a molecular weight distribution Mw/Mn of < 2.3, and a third polyethylene which is an ethylene copolymer or homopolymer having a weight average molecular weight of from 100,000 to 300,000 and a molecular weight distribution Mw/Mn of > 2.3, where the first polyethylene has more short chain branching than the second polyethylene or the third polyethylene. The polyethylene composition has a soluble fraction in a CEF analysis of at least 15 weight percent. Film made from the polyethylene composition may have a machine direction 1% secant modulus of ≥ 200 MPa (at a film thickness of about 1 mil) and an oxygen transmission rate (OTR) of ≥ 700 cm3 per 100 inch2 (at a film thickness of about 1 mil). Film made from the polyethylene composition retains much of its dart impact performance on downgauging from a thickness of 1 mil to a thickness of 0.75 mil. |