Elastic substantially linear ethlene polymers
US5986028A · kind A · utility
Assignee
Inventors
Key dates
| Filing date | Nov 26, 1997 |
| Grant date | Nov 16, 1999 |
| Priority date | — |
| Expiry date | Nov 26, 2017 |
Classification
- Technology area (CPC Y)Emerging Cross-Sectional Technologies
- CPC primaryY10S526/943
- WIPO fieldMacromolecular chemistry, polymers
- WIPO sectorChemistry
Abstract
A continuous polymerization process of preparing ethylene polymers containing less than about 20 ppm aluminum, and having processability similar to highly branched low density polyethylene (LDPE), but the strength and toughness of linear low density polyethylene (LLDPE). The polymers have processing indices (PI's) less than or equal to 70 percent of those of a comparative linear ethylene polymer and a critical shear rate at onset of surface melt fracture of at least 50 percent greater than the critical shear rate at the onset of surface melt fracture of a traditional linear ethylene polymer at about the same I.sub.2 and M.sub.w /M.sub.n. The novel polymers can also have from about 0.01 to about 3 long chain branches/1000 total carbons and have higher low/zero shear viscosity and lower high shear viscosity than comparative linear ethylene polymers. The novel polymers can also be characterized as having a melt flow ratio, I.sub.10 /I.sub.2, .gtoreq.5.63, a molecular weight distribution, M.sub.w /M.sub.n, defined by the equation: M.sub.w /M.sub.n .ltoreq.(I.sub.10 /I.sub.2)-4.63, a critical shear stress at onset of gross melt fracture greater than about 4.times.10.sup.6 dyne/cm.sup.2,…
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.