FIELD: methods of production of cellulose extrudates from optically anizotropic solutions. SUBSTANCE: cellulose extrudates are produced from optically anizotropic solution containing 94-100 wt.% of the following components: cellulose, phosphoric acid and/or its anhydrates and water. Extrudates are produced by solution extrusion and coagulation of formed extrudates. They are additionally treated to obtain their degree of acidity equalling at least 7, strength preservation efficiency of 80% or above, and content of phosphorous combined with cellulose of 0.02-3.00 wt.%. EFFECT: higher heat resistance of fibers and their efficient use as reinforcing material. 5 cl, 1 tbl, 3 ex
