| 摘要 |
PURPOSE:To obtain carbon fibers, having high specific tensile strength and specific elasticity, and useful for industrial materials, etc., by flameproofing polyacrylonitrile fibers in an oxidizing atmosphere under specified conditions, and carbonizing the resultant fibers in an inert atmosphere in a furnace divided into plural parts at different maximum temperatures. CONSTITUTION:Fibrous bundles or weblike materials formed from polyacrylonitrile or an acrylonitrile copolymer as a raw material are calcined in an oxidizing atmosphere at 200-400 deg.C to give flameproofed fibers 1, which are then carbonized at a temperature in the range of 400-1,500 deg.C in an inert atmosphere in a furnace divided into plural parts of a carbonizing furnace 2 at a temperature (T1) of the maximum <= 1,000 deg.C, preferably 400-800 deg.C, and a carbonizing furnace 3 at a temperature (T2) of the maximum <=1,500 deg.C, preferably 1,100-1,300 deg.C, to afford the aimed carbon fibers. Preferably, the exhaust gas from the inert atmosphere of the carbonizing furnace 2 is expelled from a connecting part 9 through an exhaust port 8 at a temperature (T3) of 250 deg.C or above. |
