Production of stabilized acrylic fibers and films

Claim 1

AN IMPROVED PROCESS FOR THE PRODUCTION OF STABILIZED ACRYLIC FIBERS AND FILMS WHICH ARE CAPABLE OF UBDERGOING CARBONIZATION COMPRISING: A. PROVIDING A SOLUTION OF (1) AN ACRYLIC POLYMER SELECTED FROM THE GROUP CONSISTING OF AN ACRYLONITRILE HOMOPOLYLMER AND ACRYLONITRILE COPOLYMERS CONTAINING AT LEAST ABOUT 85 MOL PERCENT OF ACRYLONITRILE UNITS AND UP TO ABOUT 15 MOL PERCENT OF ONE OR MORE MONOVINYL UNITS COPOLYMERIZED THEREWIYH, (2) ABOUT 1 TO 20 PERCENT OF WEIGHT BASED UPON THE WEIGHT OF SAID ACRYLIC POLYMER OF AN ORANIC ANTIOXIDANT HAVING A MELTING POINT OF AT LEAST 200*C. CAPABLE OF MODERATING THE OXIDATIVE CROSS-LINKING REACTION OF ADJOINING ACRYLIC MOLECULES SELECTED FROM THE GROUP CONSISTING OF A NITROGEN-FREE PHENOLIC ANTIOXIDANT, AN AMINOPHENOL ANTIOXIDANT, A NON-PHENOLIC AROMATIC AMINE ANTIOXIDANT, A QUINONE ANTIOXIDANT, A SULFUR-CONTAINING ANTIOXIDANT, AND MIXTURES OF THE FOREGOING, AND (3) A SOLVENT FOR SAID ACRYLIC POLYMER AND SAID ORGANIC ANTIOXIDANT SELECTED FROM THE GROUP CONSISTING OF N, NDIMETHYLFORMAMIDE, N,N-DIMETHYLACETAMIDE, DIMETHYL SULFOXIDE, BUTYROLACTON, AND N-METHYL-2-PYRROLIDINONE, WITH SAID SOLUTION PRIOR TO STEP (B) BEING HEATED FOR INSULFFICIENT DURATION TO ACCOMPLISH A SUBSTANTIAL DEGREE OF CYCLIZATION OF PENDANT NITRILE GROUPS WHTHIN SAID ACRYLIC POLYMER WHILE DISSOLVED IN SAID SOLVENT. B. FORMING FROM SAID SOLUTION BY EXTRUSION THROUGH A SHAPED ORIFICE AN ACRYLIC FIBROUS MATERIAL OR FILM HAVING INCORPORATED THEREIN ABOUT 1 TO 10 PERCENT BY WEIGHT BASED UPON THE WEIGHT OF SAID ACRYLIC POLYMER OF SAID ORGANIC ANTIOXIDANT, AND C. HEATING SAID RESULTING ACRYLIC FIBROUS MATERIAL OR FILM IN AN OXYGEN-CONTANING ATMOSPHERE AT A TEMPERATURE OF ABOUT 200* TO 360*C. UNTIL A STABILIZED FIBROUS MATERIAL OF FILM IS FORMED WHICH RETAINS ITS ORGINAL CONFIGURATION SUBSTANTIALLY INTACT AND WHICH IS NON-BURNING WHEN SUBJECTED TO AN ORDINARY MATCH FLAME.