High tear films from hafnocene catalyzed polyethylenes
US6936675B2 · kind B2 · utility
Assignee
Inventors
Key dates
| Filing date | Dec 15, 2003 |
| Grant date | Aug 30, 2005 |
| Priority date | — |
| Expiry date | Jan 13, 2024 |
Classification
- Technology area (CPC Y)Emerging Cross-Sectional Technologies
- CPC primaryY10T428/31938
- WIPO fieldOther special machines
- WIPO sectorMechanical engineering
Abstract
A polyethylene film having a balance of improved physical and mechanical properties and a method for making the same are provided. In one aspect, the film includes a 1% secant modulus of greater than 25,000 psi, a dart impact resistance of greater than 500 g/mil, and a MD tear strength of greater than 500 g/mil. In one aspect, the method comprises reacting ethylene derived units and a comonomer in the presence of a hafnium-based metallocene at a temperature of from 70° C. and 90° C., an ethylene partial pressure of from 120 psia and 260 psia, and a comonomer to ethylene ratio of from 0.01 to 0.02 to produce an ethylene based polymer. The method further comprises extruding the ethylene based polymer at conditions sufficient to produce a polyethylene film comprising a secant modulus of greater than 25,000 psi, a dart impact resistance of greater than 500 g/mil, and a MD tear strength of greater than 500 g/mil.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.