Process for post-spin finishing of polybenzoxazole fibers
US5273703A · kind A · utility
Assignee
Inventors
Key dates
| Filing date | Aug 13, 1992 |
| Grant date | Dec 28, 1993 |
| Priority date | — |
| Expiry date | Aug 13, 2012 |
Classification
- Technology area (CPC D)Textiles; Paper
- CPC primaryD01F6/74
- WIPO fieldTextile and paper machines
- WIPO sectorMechanical engineering
Abstract
Improved polybenzoxazole fibers are made by a process for finishing a spun and drawn dope fiber, which contains polybenzoxazole polymer and a solvent acid, including the steps of: (a) coagulating the dope fiber in an aqueous coagulant: (b) washing the coagulated fiber with an aqueous washing fluid for less than 72 hours under conditions such that the fiber contains no more than 8,000 ppm residual solvent acid (1 ppm=1 part per million, by weight); (c) drying the fiber at a temperature of no more than 300.degree. C. until it retains no more than about 2 weight percent residual moisture; and (d) heat-treating the fiber at a temperature of at least about 300.degree. C. under tension.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.