Polypropylene fibers
US6146758A · kind A · utility
Assignee
Inventors
Key dates
| Filing date | May 3, 1999 |
| Grant date | Nov 14, 2000 |
| Priority date | — |
| Expiry date | May 3, 2019 |
Classification
- Technology area (CPC Y)Emerging Cross-Sectional Technologies
- CPC primaryY10T428/2967
- WIPO fieldTextile and paper machines
- WIPO sectorMechanical engineering
Abstract
Process for the production of polypropylene fibers from polypropylene polymers produced by the polymerization of polypropylene in the presence of a metallocene catalyst characterized by a bridged racemic bis(indenyl) ligand substituted at the proximal position. The polypropylene contains 0.5 to 2% 2,1 insertions and has an isotacticity of at least 95% meso diads and is heated to a molten state and extruded to form a fiber preform. The preform is subjected to spinning at a spinning speed of at least 500 meters per minutes and subsequent drawing at a speed of at least 1,500 meters per minute to provide a draw ratio of at least 3 to produce a continuous polypropylene fiber. The draw speed and/or the draw ratio can be varied to produce fibers of different mechanical properties. Different polypropylene polymers produced by different metallocene catalysts can be used. Such fibers can be characterized by having an elongation at break of at least 100% and a specific toughness of at least 0.5 grams per denier.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.