Title: Hollow synthetic fibers

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.

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Inventors: Klein, Elias (New Orleans, LA, US)
Smith, James K. (Slidell, LA, US)
Morton, Frederick C. (New Orleans, LA, US)

Application Number: 662010
Filing Date: 1976-02-27
Publication_date: 1977-09-27
Assignee: Gulf South Research Institute (Baton Rouge, LA)
Primary Class(es): 428/398 210/500.23, 210/500.28, 264/49, 264/177.14, 264/184, 264/344
Other Classes:
US Patent Ref:

2935371	May, 1960	Magat	264/184.
2955017	Oct, 1960	Boyer	264/184.
3180845	Apr, 1965	Knudsen et al.	264/182.
3242120	Mar, 1966	Steuber	260/29.
3318990	May, 1967	Kajitani	264/187.
3340340	Sep, 1967	Mytum	264/168.
3414645	Dec, 1968	Morgan	264/184.
3674628	Jul, 1972	Fabre	161/178.
3716614	Feb, 1973	Okamoto et al.	264/344.
3957651	May, 1976	Kesting	264/49.

Other Refs:
Primary Examiner: Woo, Jay H.
Assistant Examiner:
Attorney: Hoffman; Martin P., Ewing; James H., Chase; Geoffrey L.