PURPOSE: To obtain a solution from which a fibrid product can be directly prepared by reacting terephthaloyl chloride with p-phenylenediamine in a specified solvent and adding e.g. potassium hydroxide and an auxiliary solvent comprising an alcohol to the reaction mixture under agitation.

CONSTITUTION: This solution is obtained by reacting terephthaloyl chloride with p-phenylenediamine by contact under agitation in an anhydrous solution containing an N-alkylpyrrolidone and at least one anhydrous alkali (alkaline earth) metal salt to form wet acidic crumbs of a polymer and adding 2.6-5.9 mol, per mol of the NH groups of the polymer, a base such as KOH, NaOH and a 5C or lower sodium or potassium alkoxide and 10.0-38.0 mol of a auxiliary solvent represented by the formula: X-OH (wherein X is H or a 5C or lower alkyl).