High melt strength, propylene polymer, process for making it, and use thereof
US4916198A · kind A · utility
Assignee
Inventors
Key dates
| Filing date | Feb 5, 1988 |
| Grant date | Apr 10, 1990 |
| Priority date | — |
| Expiry date | Feb 5, 2008 |
Classification
- Technology area (CPC C)Chemistry; Metallurgy
- CPC primaryC08J2323/10
- WIPO fieldMacromolecular chemistry, polymers
- WIPO sectorChemistry
Abstract
Disclosed is a normally solid, high molecular weight, gel-free, amorphous to predominantly crystalline, propylene polymer characterized by high melt strength due to strain hardening which is believed to be caused by free-end long chain branches of the molecular chains forming the polymer. Also disclosed is a process for making the polymer by high energy radiation of a normally solid, high molecular weight, linear, propylene polymer in a reduced active oxygen environment, maintaining the irradiated material in such environment for a specific period of time, and then deactivating free radicals in the material. Further disclosed is the use of the strain hardening polymer in extensional flow operations such as, for example, extrusion coating, film production, and thermoforming.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.