Process for preparing acrylonitrile polymer fibers and resulting product

Claim 1

IN THE PROCESS OF PRODUCING ESSENTIALLY NON-FIBRILLATING, DYE RECEPTIVE, SHRINKABLE SYNTHETIC ACRYLONITRILE POLYMER TEXTILE FIBERS BY DISSOLVING A FIBER FORMING ACYRLONITRILE POLYMER IN AN AQUEOUS SALINE SOLVENT THEREFOR TO FORM A SALT SPINNING SOLUTION, WHICH POLYMER CONTAINS IN THE POLYMER MOLECULE AT LEAST ABOUT 85 WEIGHT PERCENT OF ACRYLONITRILE WITH ANY BALANCE BEING ANOTHER MONOETHYLENICALLY UNSATURATED MONOMERIC MATERIAL THAT IS COPOLYMERIZABLE WITH ACRYLONITRILE; SPINNING SAID FIBER FORMING ACRYLONITRILE POLYMER CONTAINING SALT SPINNING SOLUTION INTO AN AQUAGEL FILAMENTARY STRUCTURE SUBSTANTIALLY FREE FROM RESIDUAL SALT; AND SUBSEQUENTLY IRREVERSIBLY DRYING SAID AQUAGEL STRUCTURE TO A SYNTHETIC CHARACTERISTICALLY HYDROPHOBIC TEXTILE STRUCTURE; THE IMPROVEMENT CONSISTING OF (1) DISSOLVING IN SAID FIBER FORMING ACRYLONITRILE POLYMER CONTAINING SALT SPINNING SOLUTION, PRIOR TO SPINNING SAID SOLUTION INTO SAID AQUAGEL FILAMENTARY STRUCTURE, OF BETWEEN ABOUT 10 AND 30 WEIGHT PERCENT, BASED ON THE WEIGHT OF SAID FIBER FORMING ACRYLONITRILE POLYMER, OF AT LEAST ONE HYDROXYALKYL ALKYL CELLULOSE ETHER SELECTED FROM THE GROUP OF HYDROXYALKYL ALKYL CELLULOSE ETHERS HAVING FROM 1 TO 2 CARBON ATOMS IN EACH ALKYL SUBSTITUENT, FROM 2 TO 3 CARBON ATOMS IN EACH HYDROXYALKYL SUBSTITUENT, FROM 15 TO 35 PERCENT ALKOXYL SUBSTITUTION AND FROM ABOUT 2 TO 14 PERCENT HYDROXYALKYL SUBSTITUTION, AND (2) HEATING THE FIBER FORMING ACRYLONITRILE POLYMER AND HYDROXYALKYL ALKYL CELLULOSE ETHER CONTAINING SPINNING SOLUTION FOR A PERIOD OF AT LEAST ABOUT 30 HOURS AT A TEMPERATURE BETWEEN ABOUT 60*C. AND 80*C.