Method of manufacturing acrylic fibers

Method of manufacturing modacrylic fibers comprising the steps of

• A. dissolving in an organic solvent selected from the group consisting of acetone, acetonitrile, dimethylformamide and mixtures thereof a copolymer consisting essential of
• a. 30 to 80 weight percent acrylonitrile,
• b. 70 to 20 weight percent vinyl chloride or vinylidene chloride, and
• c. 0 to 3 weight percent ethylenically unsaturated monomers having a hydrophillic group and selected from the group consisting of sodium sulfopropyl methacrylate, sodium parastyrene sulfonate, sodium methacryloxybenzene sulfonate, sodium allyl sulfonate, sodium methallyl sulfonate, sodium acrylate, sodium itaconate and mixtures thereof, said copolymer being in a concentration of from 18 to 25%;
• B. adding 0.2 to 30.0 weight percent based on the weight of said copolymer of a homopolymer of glycidyl methacrylate or a copolymer consisting essentially of 30 weight percent or more of glycidyl methacrylate polymerized with one or more ethylenically unsaturated monomer selected from the group consisting of methyl acrylate, methyl methacrylate, acrylonitrile, vinyl acetate, vinyl chloride, vinylidene chloride, styrene, vinyl pyrrolidone and the like in an amount of 70 weight percent or less, wherein the specific viscosity of said homopolymer or copolymer of glycidyl methacrylate is from 0.01 to 0.50 as measured at 30.degree.C in 2.0 to 4.0 g/l acetone solution;
• C. spinning the resulting spinning solution in at least first and second baths comprising one or more said solvents in concentrations of less than 60 weight percent and 61 to 85 weight percent respectively;
• D. leading the thus obtained coagulated filaments successively through one or more subsequent baths containing 60 weight percent or less of said solvent thereby to remove said solvent and to wash said filaments;
• E. drying said filaments at about 100.degree. to 135.degree.C;
• F. stretching said filaments 2 to 4 times its length at a temperature of about 100.degree. to 135.degree.C;
• and
• G. heat treating said filaments at a temperature of about 135.degree. to 155.degree.C.