Process for wet spinning elastic fibers

摘要

1,111,807. Wet spinning elastomeric polyurethane filaments. MONSANTO CO. 20 Dec., 1965 [21 Dec., 1964], No. 83912/66. Heading B5B. Elastomeric polyurethane filaments are produced by wet spinning a solution of a segmented polyurethane polymer in an organic solvent into a coagulating bath consisting of water and the organic solvent, drawing the filaments upwards along a vertical path from the spinneret face through the coagulating bath a distance of 0À5 to 3À0, preferably 1À5 to 2À0 inches at a rate of withdrawal which will result in the filaments remaining in the bath for 0À025 to 0À2 second, preferably 0À075 to 0À1 second, so that the filaments emerge from the bath in a direction which is normal to the surface of the coagulating bath and forwarding the filaments for further processing after their emergence from the coagulating bath. The solvent may be dimethylformamide or dimethylacetamide, dimethylsulphoxide or hexamethphosphoramide. The aqueous coagulating bath is preferably maintained at about 60‹ to 90‹ C. and the percentage of organic solvent in the bath may be about 1 to 40%. In an example, the polymer solution is formed by first forming a solution of a " prepolymer " by reacting a polycaprolactone with 4,41 methylenediphenyl diisocyanate in dimethylformamide solvent and the solution is added to a solution of ethylene diamine in dimethylformamide to give a spinning dope containing 15% solids. In all the examples the filaments formed are washed, dried and taken up after their emergence from the bath.