Abstract: Process for the batchwise preparation of poly-p-phenylene terephthalamide polymer by means of reacting approximately equimolar amounts of p-phenylene diamine and terephthaloyl dichloride in a solution containing N-methyl-2-pyrrolidone and calcium chloride, with the reaction being carried out in a cylindrical reaction vessel equipped with a single mixing gear used as stirrer and granulator, the contents of the reaction vessel being whirlingly mixed as terephthaloyl dichloride is added, the formed polymer being crumbled, and the reaction and the crumbling taking place in one and the same reaction vessel. The whirling miming ensures that the terephthaloyl dichloride is very thoroughly mixed into the solution of N-methyl-2-pyrrolidone, calcium chloride, and p-phenylene diamine before the reaction between the reactants causes a very rapid increase in viscosity. The quality of She product obtained by this process is very high.