Method of making high-shrink textile fibers

Claim 1

METHOD OF PREPARING A HIGHLY SHRINKABLE SYNTHETIC ACRYLONITRILE POLYMER TEXTILE FIBER WHICH METHOD COMPRISES SALT SPINNING A FIBER-FORMING ACRYLONITRILE POLYMER THAT IS ADAPTED TO PROVIDE FIBERS WHICH DO NOT SHRINK MORE THAN 15 PERCENT AFTER EXPOSURE TO WATER AT ABOUT 100*C., WHICH POLYMER CNTAINS IN THE POLYMER MOLECULE AT LAST ABOUT 80 PERCENT OF ACRYLONTRILE, 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, SAID AQUAGEL HAVING INCORPORATED THEREIN BETWEEN ABOUT 2 AND 15 WEIGHT PERCENT, BASED ON THE DRY WEIGHT OF THE COMBINED POLYMER COMPOSITION, OF A POLYMER OF A MONOMER SELECTED FROM THE GROUP CONSISTING OF A N-VINYL LACTAM, A N-VINYL-3-MORPHOLINONE, A N-VINYL-2OXAZOLIDINONE, AND A N-VINYL:METHYLALKYL:SULFONAMIDE; WASHING SAID AQUAGEL SUBSTANTIALLY FREE FROM RESIDUAL SALT AND PHYSICALLY ELONGATING SAID FIBER BY STRETCHING IT TO AN AT LEAST PARTIALLY ORIENTED CONDITION; SUBJECTING SAID AQUAGEL FIBER TO INTIMATE CONTACT WITH AN AQUEOUS SOLUTION OF A SULFOSUCCINATE OF THE STRUCTURE: