Polyamide fibers having improved properties, and their production
Abstract
Abstract A polyamide fiber excellent in strength, which comprises at least one of polycapramide, polyhexamethylene adipamide and polytetramethylene adipamide in an amount of not less than 60% by weight on the basis of the polyamide fiber and which is characterized by having a relative viscosity of not less than 2.3 and less than 3.5 (measured on a 96% by weight sulfuric acid solution having a polyamide concentration of 10 mg/ml at 20° C.), an index of birefringence (Δn) (measured after 24 hours under the conditions of 30° C. and 80% relative humidity) of not less than 55×10 -3 and a tenacity of not less than 12.0 g/d, the index of birefringence in section satisfying the following relationship: Δn.sub.A -Δn.sub.B ≧0 (wherein Δn A is the index of birefringence of fiber at the position of r/R=0.9, Δn B is the index of birefringence of fiber at the position of r/R=0.0, R is the radius of the fiber section and r is the distance from the central axis of the fiber section) and the tenacity and the break elongation satisfying the following relationship: ##EQU1##
Inventors
- 👤 Kazuo Kurita
- 👤 Hideaki Ishihara
Bibliographic Details
Claims Analysis
Total Claims: 9References Cited (Backward Citations)
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1990-10-19 | 1991-04-20 | 1991-10-20 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1994-10-19 | 1995-04-20 | 1995-10-20 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1998-10-19 | 1999-04-20 | 1999-10-20 | $7700.00 | Window Closed / Lapsed |