METHOD FOR PREPARING CARBON FIBER Russian patent published in 2007 - IPC D01F9/22 

FIELD: chemical technology.

SUBSTANCE: invention relates to technology for preparing carbon fibers. Method involves thermal treatment of thermostabilized fiber consisting of homo- or copolymers of acrylonitrile at heating to 1200-2400°C and removing pyrolysis products by countercurrent of inert gas. In zone with maximal temperature the gas rate flow is increased by 4-7 times, i. e. from 18 to 72-126 m/min. Time for thermal treatment of fiber in this zone is 10-20% of the total thermal treatment time. The sodium content is decreased from 0.3% in the parent acrylonitrile fiber to 0-0.02% in carbon fiber after thermal treatment. The onset combustion temperature of carbon fiber is increased from 450°C to 480-660°C in case for constant inert gas feeding, and increasing the content of sodium from 0.1% in the parent acrylonitrile fiber to 0.14% in carbon fiber.

EFFECT: improved preparing method.

1 tbl, 10 ex