Highly oriented aromatic polyamide short fiber
US4511623A · kind A · utility
Assignee
Inventors
Key dates
| Filing date | Aug 16, 1983 |
| Grant date | Apr 16, 1985 |
| Priority date | — |
| Expiry date | Aug 16, 2003 |
Classification
- Technology area (CPC Y)Emerging Cross-Sectional Technologies
- CPC primaryY10T428/2976
- WIPO fieldTextile and paper machines
- WIPO sectorMechanical engineering
Abstract
High oriented poly(p-phenylenetetraphthalamide) short fibers having an inherent viscosity of at least 5.0 and a dimension of 2-12 .mu.m in diameter and 1000-5000 .mu.m in length are provided. These fibers have a physical form of irregular cross-sections and needle point-like ends similar to those of natural wood pulp fibers, and crystalline properties such as a crystallinity of more then 50%, an orientation angle of less than 25.degree. and an apparent crystallite size of more that 50 .ANG. as determined from an X-ray diffractogram scan, and a cross-section with four extinction positions through 360.degree. rotation when observed under a polarizing microscope. These fibers are prepared, without spinning steps, by subjecting the molecular chains of poly(p-phenyleneterephthalamide) to mechanical parallelization during the growth of the chains in a polymerization system therefor containing a pyridine/amide-based solvent.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.