Method for processing polyethylene having a molecular weight of at least 400,000 by heating at an elevated pressure
US6433120B1 · kind B1 · utility
Assignee
Inventors
Key dates
| Filing date | Oct 27, 1999 |
| Grant date | Aug 13, 2002 |
| Priority date | — |
| Expiry date | Oct 27, 2019 |
Classification
- Technology area (CPC B)Performing Operations; Transporting
- CPC primaryB29K2023/0683
- WIPO fieldOther special machines
- WIPO sectorMechanical engineering
Abstract
A method for processing ultra-high molecular weight polyethylene (UHMWPE) of at least 400,000 by heating under an elevated pressure, followed by cooling, wherein UHMWPE having a lamellar thickness <12 nm and a melting temperature at atmospheric pressure >141° C. is used, by carrying out the heating under an elevated pressure via a transient hexagonal phase, which phase is represented by the hatched area in the Figure, which lies below the equilibrium line of the phase transition orthorhombic phase—liquid phase, which area is enclosed by points (P1, T1′), (P2, T1′), (P2, T2) and (P1, T1 ), wherein T1 and T2 represent the equilibrium temperatures associated with pressures P1 and P2 respectively, followed by heating to melting and cooling to ambient temperature.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.