Process of producing non-fibrillating acrylonitrile polymer filaments

Claim 1

METHOD OF PREPARING A NON-FIBRILLATING SYNTHETIC ACRYLONITRILE POLYMER TEXTILE FIBER WHICH METHOD COMPRISES: (A) SALT SPINNING A FIBER-FORMING ACRYLONITRILE POLYMER, WHICH POLYMER CONTAINS IN THE POLYMER MOLECULE AT LEAST ABOUT 85 WEIGHT PERCENT OF ACRYLONITRILE, ANY BALANCE BEING ANOTHER MONOETHYLENICALLY UNSATURATED MONOMERIC MATERIAL THAT IS COPOLYMERIZABLE WITH ACRYLONITRILE, INTO AN AQUAGEL FILAMENTARY STRUCTURE THAT CONTAINS BETWEEN ABOUT 1 AND 5 PARTS BY WEIGHT OF WATER TO EACH PART BY WEIGHT OF DRY POLYMER THEREIN; (B) WASHING SAID AQUAGEL STRUCTURE SUBSTANTIALLY FREE FROM RESIDUAL SALT; (C) PHYSICALLY ELONGATING SAID AQUAGEL STRUCTURE BY STRETCHING IT TO AN AT LEAST PARTIALLY ORIENTED CONDITION; (D) SUBJECTING FOR FROM 2 MINUTES TO ABOUT 4 HOURS THE SO-FORMED AQUAGEL FIBER TO INTIMATE CONTACT WITH A HOMOGENEOUS AQUEOUS EMULSION CONTAINING AT LEAST 1 WEIGHT PERCENT OF A SUBSTANTIALLY WATER-INSOLUBLE POLYOXYALKYLENE GLYCOL HAVING AN AVERAGE MOLECULAR WEIGHT BETWEEN ABOUT 1000 AND 3000 AND A VISCOSITY AT 100*F. BETWEEN ABOUT 100 AND 260 CENTISTOKES, SAID EMULSION MAINTAINED AT A TEMPERATURE BETWEEN ABOUT 60*C. AND 100*C.; AND (E) SUBSEQUENTLY IRREVERSIBLY DRYING SAID AQUAGEL FIBER TO A SYNTHETIC CHARACTERISTICALLY HYDROPHOBIC TEXTILE FIBER STRUCTURE.