Porous fibers and membranes and methods for their preparation and use

US4744906A · kind A · utility

Assignee

• Akzo N.V. · NL

Inventors

• Klaus Gerlach · Aschaffenburg, DE
• Erich Kessler · Kelsterbach, DE

Key dates

• Filing date: Oct 4, 1985
• Grant date: May 17, 1988
• Expiry date: Oct 4, 2005

Classification

• Technology area (CPC C): Chemistry; Metallurgy
• CPC primary: C08J2201/0546
• WIPO field: Chemical engineering
• WIPO sector: Chemistry

Abstract

The invention concerns porous fibers and membranes, methods for their preparation and for their use. The fibers are characterized by a smooth porous surface and an apparent density of between about 10 to 90% of the true density of the polymeric starting material employed. The process involves the formation of a homogeneous mixture of at least two components, one of which is a meltable polymer and another liquid inert with respect to the polymer. The mixture formed must be of a binary type, in which there is a temperature range of complete miscibility and a range in which there is a miscibility gap. The mixture is extruded at a temperature above the separation temperature into a bath containing at least some of the inert liquid which is at a temperature below the separation temperature. Upon introduction of the mixture into the bath, the fiber structure of the product is fixed.