| 摘要 |
<FORM:0937685/IV(a)/1> Polymers containing at least 85% polyacrylonitrile, any balance being copolymers therewith, are dissolved in 55-65% aqueous zinc halide, and the resulting solution is spun into an aqueous coagulating bath containing a 5-35% solution of the same zinc halide and held at 5 DEG -25 DEG C., and the resulting tow stretched in saturated steam or in an aqueous medium held at at least 100 DEG C., and reeled in a spinning pot, the stretched tow being brought into contact with hot water at substantially 100 DEG C. in the funnel of the spinning pot and thereby subjected to 20-35% shrinkage and then desalted by spraying with hot water, while being reeled on the spinning pot. Specified zinc halides include the chloride, bromide and iodide. Polymerization of the constituent monomers may be effected in the spinning solvent, which may also contain an organic or inorganic acid, e.g. acetic or hydrochloric acid. Desirably, polymers containing at least 93% polyacrylonitrile are spun into a coagulating bath having a zinc halide concentration of 20-35% and maintained at 5 DEG -15 DEG C., while polymers containing 85-92% polyacrylonitrile are more suitably spun into a coagulating bath having a zinc halide concentration of 5-15% and maintained at 15 DEG -25 DEG C. An intermediate drying step to less than 3% water is desirable after stretching polymers containing over 93% polyacrylonitrile. As shown, the freshly-spun tow 3 is subjected to saturated steam in the chamber 5 while passing around rollers 4, and stretched between rollers 5 and 6. Heated rollers 7 may be used to effect the intermediate drying step when required. While passing through the funnel 9 of spinning pot 8 the filaments are sprayed through the pipe 11 to effect shrinkage, and are desalted by a spray of hot water supplied from pipe 13 and issuing at the foot of the funnel 12 while being reeled on the spinning pot.
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