Process for dyeing and printing nickel-containing polyolefins

A process for the dyeing and printing of nickel-containing polyolefin fiber which comprises bringing said material into contact with a dyestuff of the formula ##STR9## wherein R is hydrogen, lower alkyl, phenyl-(lower alkylene), phenyl-(lower-alkylene) substituted in the benzene nucleus by 1 to 2 substituents of the group consisting of chlorine, cyano, hydroxy, carbalkoxy having 2 to 5 carbon atoms and carboxylic acid amide, or R is phenyl or phenyl substituted by 1 or 2 substituents of the group consisting of chlorine, lower alkyl, lower alkoxy, cyano, carbonamide and sulfonamide, R.sub.1 is hydrogen, lower alkyl, lower alkyl substituted by 1 or 2 substituents of the group consisting of carbalkoxy of 2 to 5 carbon atoms and carboxylic acid amide, or is phenyl or phenyl substituted by 1 or 2 substituents of the group consisting of chlorine, lower alkyl, lower alkoxy, cyano, carboxylic acid amide and sulfonic acid amide, R.sub.2 is hydrogen, lower alkyl, lower alkyl substituted by 1 or 2 substituents of the group consisting of carbalkoxy having 2 to 5 carbon atoms and carboxylic acid amide, or is phenyl or phenyl substituted by 1 or 2 substituents of the group consisting of chlorine, lower alkyl, lower alkoxy, cyano, carboxylic acid amide and sulfonic acid amide, or is halogen, nitro, cyano, thiocyanate, carbalkoxy having 2 to 5 carbon atoms, alkylcarbonyl having 2 to 5 carbon atoms, carbamoyl, carbamoyl mono- or disubstituted by 1 or 2 alkyl having 1 to 4 carbon atoms or by 1 alkyl of 1 to 4 carbon atoms and one phenyl or by phenyl, and R.sub.3 is alkyl having 1 to 4 carbon atoms.