Aromatic polyamides containing disulphimide - groups

High-molecular aromatic polyamides which can be dyed by means of basic dyes contain 2-20 mol % (of the total units derived from the diamine or from the dicarboxylic acid dihalide) of a disulphimide group containing units of formula: where Ar1 and Ar2 are divalent aromatic residues consisting of 1, or several condensed, aromatic rings, or aromatic rings joined by a simple bond or a -CH2-, -O-, or -SO2- group, and which may carry alkyl or halogen substituents, Ar3 is a trivalent aromatic residue, R is Cl-4 alkyl or a residue which may be alkyl- or halogen-substd, Z is H or an alkali metal and A is -CONH- or -NHCO-, and 98-80 mol % of units from known aromatic polyamides. The polyamide has a relative solution viscosity (using a 0.5% solution in N-methyl-pyrrolidone at 20 degrees C)>1.3. The polyamides are almost colourless and are very easily dyed with basic dyes.