Process for direct on-bobbin heat treating of high denier filaments of thermotropic liquid crystalline polymers
US6129878A · kind A · utility
Assignee
Inventors
Key dates
| Filing date | Sep 10, 1998 |
| Grant date | Oct 10, 2000 |
| Priority date | — |
| Expiry date | Sep 10, 2018 |
Classification
- Technology area (CPC D)Textiles; Paper
- CPC primaryD01F6/84
- WIPO fieldTextile and paper machines
- WIPO sectorMechanical engineering
Abstract
The present invention discloses and claims a novel process for the heat treatment of high denier filaments of a thermotropic liquid crystalline polymer. Preferred embodiments include process for the formation of heat treated filaments of a few wholly aromatic polyesters and polyesteramides. The process involves: (a) heating of a thermotropic liquid crystalline polymer to above its melting transition temperature; (b) passing said molten polymer through an extrusion chamber equipped with an extrusion capillary of an aspect ratio of greater than about 1 and less than about 15 to form a filament; (c) winding the filament on to a bobbin at a low tension and draw-down ratio of at least about 4; and (d) heat treating the filament directly on the bobbin at suitable temperature and pressure conditions for a sufficient period of time. The filaments so formed are of at least 50 denier per filament (dpf) and feature essentially uniform molecular orientation across the cross-section. The heat-treated filaments feature remarkably good tensile properties retaining at least 80 to 90 percent of the properties expected of conventional low denier (5 to 10 dpf) filaments.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.