Process of spinning acrylonitrile polymer filaments from solution of dimethyl sulfoxide and a non-solvent

Claim 1

THE PROCESS COMPRISING THE STEPS OF ADMIXING AT LEAST 10% BY WEIGHT OF A POLYMER OF ACRYLONITRILE CONTAINING AT LEAST ABOUT 85% BY WEIGHT OF COMBINED ACRYLONITRILE IN A MIXED SOLVENT MEDIUM COMPRISING FROM ABOUT 40% TO ABOUT 80% BY VOLUME OF DIMETHYL SULFOXIDE AND AN ORGANIC NON-SOLVENT FOR THE ACRYLONITRILE POLYMER HAVING A BOILING POINT BETWEEN ABOUT 40* C. AND 150* C. SELECTED FROM TEH GROUP CONSISTING OF ACETONE, METHYL ETHYL KETONE, 4-METHYLPENTANONE-2, DIETHYL ETHER, 1,2DIMETHOXYETHANE, TETRAHYDROFURAN, 1,3-DIOXANE, DIOXOLANE, ACETONITRILE, ETHYL ACETATE, N-AMYL ACETATE, METHYLENE CHLORIDE, CARBON TETRACHLORIDE, BENZENE, AND TOLUENE, DISSOLVING SAID POLYMER IN SAID SOLVENT MEDIUM BY HEATING THE MIXTURE TO FORM A SOLUTION CONTAINING AT LEAST ABOUT 10% BY WEIGHT OF THE ACRYLONITRILE POLYMER AND HAVING A VISCOSITY BETWEEN ABOUT 25 AND ABOUT 750 POISES, AND SPINNING THE SOLUTION INTO A FILAMENT AT A TEMPERATURE SUBSTANTIALLY LESS THAN THAT REQUIRED FOR SPINNING A SOLUTION OF THE SAME ACRYLONITRILE POLYMER IN DIMETHYL SULFOXIDE AND HAVING SUBSTANTIALLY THE SAME VISCOSITY AS THE SOLUTION OF THE POLYMER IN THE MIXED SOLVENT MEDIUM.