POLYETHYLENE COMPOSITION AND FILM HAVING HIGH STIFFNESS, OUTSTANDING SEALABILITY AND HIGH PERMEABILITY

摘要

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 from 15,000 to 100,000, 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 70,000 to 250,000 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 10 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), a seal initiation temperature (SIT) of ≤ 90°C (at a film thickness of about 2 mil), an area of hot tack window (AHTW) of ≥ 160 Newtons∙C° (at a film thickness of about 2 mil) and an oxygen transmission rate (OTR) of ≥ 600 cm³ per 100 inch² (at a film thickness of about 1 mil).