Thermal treatment of irradiated propylene polymer material
US5047446A · kind A · utility
Assignee
Inventor
Key dates
| Filing date | Jul 22, 1988 |
| Grant date | Sep 10, 1991 |
| Priority date | — |
| Expiry date | Jul 22, 2008 |
Classification
- Technology area (CPC Y)Emerging Cross-Sectional Technologies
- CPC primaryY10S522/915
- WIPO fieldMacromolecular chemistry, polymers
- WIPO sectorChemistry
Abstract
Disclosed is a method of treating a free-radical-containing, optionally room-temperature-aged, irradiated, normally solid high-molecular-weight, semi-crystalline propylene polymer material at about from 40.degree. C. to 110.degree. C. for at least about 10 minutes before being exposed to the higher temperatures that deactivate the residual free radicals therein. Treatment of the polymer at the intermediate temperature causes recombination, and better utilization, of free radicals with the production of more long-chain branching. A two-stage fluid bed process, with a first stage at the intermediate temperature for radical recombination and a second radical-deactivation stage at a higher temperature, is preferred.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.