Process for the production of dry-spun hollow polyacrylonitrile fibers and filaments

US4432923A · kind A · utility

Assignee

• BAYER HEALTHCARE LLC · DE

Inventors

• Ulrich Reinehr · Dormagen, DE
• Toni Herbertz · Dormagen, DE
• Hermann-Josef Jungverdorben · Dormagen, DE
• Hans K. Burghartz · Neuss, DE

Key dates

• Filing date: Jun 9, 1982
• Grant date: Feb 21, 1984
• Expiry date: Jun 9, 2002

Classification

• Technology area (CPC D): Textiles; Paper
• CPC primary: D01F6/18
• WIPO field: Chemical engineering
• WIPO sector: Chemistry

Abstract

Hollow polyacrylonitrile fibers having a uniform closed cavity structure are obtained by dry-spinning filament-forming acrylonitrile polymers from a solution through a spinning jet comprising annular jet bores of the type shown in FIG. 1, the solution having a viscosity of at least 120 falling-ball seconds, as measured at 80.degree. C. or of at least 75 falling-ball seconds, as measured at 100.degree. C., the ring of the annular jet bores consisting of three, preferably equally large, ring segments at a distance from one another of at most 0.2 mm, the surface area of the jet bores of the profile jet amounting to less than 0.2 mm.sup.2 and the side width of the ring segments amounting to at most 0.1 mm, the spinning air acting on the filaments transversely of the direction in which they are taken off relative to the center of the spinning jet.