Frederick C Morton

US Patent:

40513009, Sep 27, 1977

Filed:

Feb 27, 1976

Appl. No.:

5/662010

Inventors:

Elias Klein - New Orleans LA
James K. Smith - Slidell LA
Frederick C. Morton - New Orleans LA

Assignee:

Gulf South Research Institute - Baton Rouge LA

International Classification:

B05D 300
D02G 322

US Classification:

428398

Abstract:

Hollow synthetic fibers useful in reverse osmosis, ultrafiltration, gas separation and the like, having high hydraulic permeability to the solvent and capable of operation at pressures from 600 psi and up, are prepared by forming a solution of a fiber-forming polymer in a suitable solvent, adding to the solution a second polymer soluble in the solvent but with limited compatibility with the first polymer when their total concentration increases on coagulation, extruding the resulting solution through an orifice equipped for coaxial extrusion so that coagulating fluid within tube flow results, precipitating with a liquid which is miscible with the solvent for the fiber-forming material, is a non-solvent for the first polymer and a solvent for the second, contacting the extruded solution with the precipitating liquid either coaxially through the extrusion device or by passing the extrudate through the precipitating liquid, and finally washing the resulting hollow fiber free of residual solvents and non-solvents, and air drying. The coagulating fluid and the precipitating liquid may be the same material. The coagulating fluid may be air or another gas.