Non-flammable, high-temperature resistant polyimide fibers made by a dry spinning method

US4801502A · kind A · utility

Assignee

• Chemiefaser Lenzing Aktiengesellschaft · AT

Inventors

• Klaus Weinrotter · Vöcklabruck, AT
• Thomas Jeszenszky · Kammer, AT
• Heinrich Schmidt · Düsseldorf, DE
• Siegfried Baumann · Vöcklabruck, AT
• Johann Kalleitner · Neumarkt am Wallersee, AT

Key dates

• Filing date: May 11, 1987
• Grant date: Jan 31, 1989
• Expiry date: May 11, 2007

Classification

• Technology area (CPC Y): Emerging Cross-Sectional Technologies
• CPC primary: Y10T428/2973
• WIPO field: Textile and paper machines
• WIPO sector: Mechanical engineering

Abstract

Non-flammable, high-temperature resistant polyimide fibers have irregularly lobed or serrated cross-sections, a wool-like smooth hand and high brightness. They are produced by a dry-spinning process which is carried out in a spinning column, wherein a 20 to 40% solution of the polyimide is spun from spinnerets having circular orifices, the orifice numbers ranging from 20 to 800 and the orifice diameters from 100 to 300 .mu.m. An extrusion speed of between 20 and 100 m/min, a take-up speed of between 100 and 800 m/min, an amount of spin gas between 40 and 100 m.sup.3 /h under standard conditions and a spin gas temperature of between 200.degree. and 350.degree. C. are applied. The tows leaving the spinning column, which contain residual solvent from 5 to 25% by weight--based on dry polymer--and have a single filament titer of between 3.5 and 35 dtex, are washed in hot water, then they are dried to a moisture content of less than 5%, subsequently are drawn at high temperatures and, if desired, are crimpled and cut into staple fibers.