Patent ID: 6967014

Claim:
A method of obtaining a carbon fiber fabric by carbonizing a cellulose fiber fabric, the method comprising: (a) admitting a cellulose fiber fabric having warp and weft yarns to be carbonized through an inlet to a carbonization chamber; (b) causing the cellulose fiber fabric to be subjected to a heat treatment by travelling continuously through the carbonization chamber between said inlet and an outlet of the carbonization chamber, wherein a method of said heat treatment comprises: (i) entering an initial chamber stage at said inlet of the carbonization chamber for bringing the temperature of the cellulose fiber fabric entering the carbonization chamber to a value lying in the range 250° C. to 350° C., the initial stage comprising temperature rise at a first mean speed lying in the range 10° C./min to 60° C./min; (ii) exiting the initial chamber stage and entering an intermediate stage for raising the temperature of the fabric to a value lying in the range 350° C. to 500° C., the intermediate stage comprising temperature rising at a second mean speed lower than the first and lying in the range 2° C./min to 10° C./min; and (iii) departing the intermediate chamber stage and entering a final stage for raising the temperature of the fabric to a value lying in the range 500° C. to 750° C., the final stage comprising temperature rising at a third mean speed greater than the second and lying in the range 5° C./min to 40° C./min; and (c) retrieving a carbon fiber fabric resulting from carbonization of said cellulose fiber fabric at the outlet of the carbonization chamber.