Method for spinning carbon fibers

Claim 1

A method for spinning carbon fibers by subjecting petroleum-origin or coal-tar-origin pitch to heat-treatment to obtain a mesophase-containing pitch, separating a mesophase from the resulting pitch and subjecting the separated mesophase to the melt-spinning, which comprises injecting an inert gas or a non-oxidative gas of lower boiling point hydrocarbons, which is heated up to a predetermined temperature which is about 30°˜60° C. lower than the spinning temperature, directly onto the surfaces of spinning nozzles steadily at a spinning temperature of molten pitch of 250° C. to 400° C. to maintain the temperature of the surfaces of spinning nozzles at a predetermined temperature while keeping an angle of injection of gas of 30°˜80° relative to falling spun filaments and an injection speed of gas in the range of 5˜70 cm/sec, thereby preventing the raw filament yarns extruded from the spinning nozzles from immediately turning to infusible thermosetting matter, and immediately driving gaseous components, which are vaporized from the spinning nozzles and raw filament yarns, off the surfaces of spinning nozzles to control the contamination of the surfaces of spinning nozzles.

Claim 2

A method for spinning carbon fibers by subjecting petroleum-origin or coal-tar-origin pitch to heat-treatment to obtain a mesophase-containing pitch, separating a mesophase from the resulting pitch and subjecting the separated mesophase to the melt-spinning, which comprises injecting an inert gas or a non-oxidative gas of lower boiling point hydrocarbons, which is heated up to a predetermined temperature which is about 30°˜60° C. lower than the spinning temperature, directly onto the surfaces of spinning nozzles steadily at a spinning temperature of molten pitch of 250° C. to 400° C. to maintain the temperature of the surfaces of spinning nozzles at a predetermined temperature while keeping an angle of injection of gas of 30°˜80° relative to falling spun filaments and an injection speed of gas in the range of 5˜70 cm/sec, thereby preventing the raw filament yarns extruded from the spinning nozzles from immediately turning to infusible thermosetting matter, and immediately driving gaseous components, which are vaporized from the spinning nozzles and raw filament yarns, off the surfaces of spinning nozzles to control the contamination of the surfaces of spinning nozzles.