| 摘要 |
PURPOSE:To obtain the titled yarn having extremely high tensile strength by simple facilities and in a short process, by making precursor having a relatively small amount of acrylonitrile unit and strength of >=fixed level fireproof and carbonizing the precursor in a gas atmosphere having a specific composition. CONSTITUTION:First, polyacrylonitrile yarn having 90-97wt.% acrylonitrile unit and >=7g/d strength of single yarn is heat-treated in an oxidizing atmosphere such as air, etc., generally at 200-300 deg.C. Then the prepared fireproof yarn is heat-treated in an inert gas atmosphere containing steam and a halogenated hydrocarbon (preferably HCl) as constituent components and carbonized to give the aimed yarn. Preferably the inert atmosphere gas is fed to a temperature range of 1,000-1,450 deg.C of a carbonizing furnace and carbonization is preferably carried out while providing the yarn with -15-20% elongation.
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