Polyolefin resin blends for crack-resistant pipe
US8475898B2 · kind B2 · utility
Assignee
Inventors
Key dates
| Filing date | Aug 29, 2007 |
| Grant date | Jul 2, 2013 |
| Priority date | — |
| Expiry date | Oct 14, 2030 |
Classification
- Technology area (CPC Y)Emerging Cross-Sectional Technologies
- CPC primaryY10T428/1397
- WIPO fieldOther special machines
- WIPO sectorMechanical engineering
Abstract
Resin blends useful for pipe and blow-molded articles are disclosed. The blends comprise a low-molecular-weight, high-density polyethylene and a high-molecular-weight, low-density ethylene copolymer. The high-molecular-weight component is made with a bridged indenoindolyl Group 4 metal complex having open architecture. Blends of the invention uniquely have high molecular weight (Mw>200,000) and low levels of long-chain branching. A quick, convenient approach for estimating levels of long-chain branching in polyethylenes from gel permeation chromatography and dynamic oscillatory rheometry (“viscosity enhancement factor”) is disclosed.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.