Dyeing process using quaternary ammonium salt as retarder

In a process for dyeing an anionic polyacrylonitrile fibrous material with a basic dye in the presence of a retarder, the improvement which comprises using as the retarder in said dyeing process a salt containing quaternary ammonium groups and having the formula ##STR8## in which each radical R.sup.1 is a linear or branched and unsubstituted or hydroxyl-substituted alkyl of one to six carbon atoms or in which two radicals R.sup.1 joined to a common nitrogen atom form therewith a heterocylic radical of four to seven carbon atoms;

• R.sup.2, R.sup.3 and R.sup.4, respectively, are a cyclic, linear or branched, saturated or olefinically unsaturated and unsubstituted or hydroxyl-substituted alkyl of one to 30 carbon atoms or said alkyl is interrupted by one or more ether bridges, or an unsubstituted, chloro-substituted or alkyl-substitute phenyl or benzyl group of one to twelve carbon atoms in the alkyl substituents, and R.sup.3 and R.sup.4 may also be hydrogen or a free electron pair;
• R.sup.5 is hydrogen or alkyl of one to four carbon atoms;
• Z is an unsubstituted or hydroxyl-substituted alkylene of two to six carbon atoms or said alkylene radical which is interrupted by ether groups;
• X.sup.(-) is the organic or inorganic anion of an alkylating agent;
• and n is a number of from 1 to 3.