Process for preparing aromatic polyamides

The present invention relates to a process for preparing an aromatic polyamide which comprises: (A) a dicarboxylic acid component unit comprising 30 to 100 mol % of a terephthalic acid component unit, and, as required, 0 to 70 mol % of a cyclic dicarboxylic acid component unit other than the terephthalic acid and, as required, 0 to 15 mol % of an aliphatic dicarboxylic acid having 7 to 20 carbon atoms; and (B) a diamine unit comprising 50 to 100 mol % of a component unit derived from an aliphatic alkylene diamine having 4 to 25 carbon atoms, and 0 to 50 mol % of a component unit derived from an alicyclic diamine having 3 to 25 carbon atoms; said process comprising: a step (i) of preparing a solid low-degree condensation product having an intrinsic viscosity [ eta ]1 of from 0.05 to 0.2 dl/g is prepared by the polycondensation reaction of the dicarboxylic acid with the diamine; a step (ii) of solid-phase polymerizing said low-degree condensation product at a temperature of not higher than 195 DEG C. to prepare a solid-phase polymerized product having having an intrinsic viscosity [ eta ]2 satisfying the following relationship [I],[ eta ]2-[ eta ]1=0.02 to 0.1 dl/g [I] and; a step (iii) of further solid-phase polymerizing said solid-phase polymerized product to obtain an aromatic polyamide having an intrinsic viscosity [ eta ]3 of from 0.15 to 1.1 dl/g and a ratio [ eta ]3/[ eta ]2 of not smaller than 1.0.