Polyester fibers dyed with a disazo disperse dyestuff

A polyester fiber dyed with a disazo disperse dyestuff free from --SO.sub.3 H groups imparting solubility in water of the formula ##SPC20##

• in which
• X represents hydroxyl or --NH.sub.2, R.sub.1 and R.sub.2 each represents hydrogen, phenyl, C.sub.1 -C.sub.2 -alkyl, C.sub.1 -C.sub.2 -alkoxy, and when X = OH, also C.sub.1 -C.sub.2 -alkoxycarbonyl or --CONH.sub.2,
• Z represents --O--, --S--, --NH-- cyclohexylidene, C.sub.1 -C.sub.2 -alkylene, --O--(C.sub.1 -C.sub.2 -alkylene)--O--, and
• R.sub.3 and R.sub.4 each represent hydrogen, C.sub.1 -C.sub.2 -alkyl, C.sub.1 -C.sub.2 -alkoxy or chlorine, and
• D.sub.1 and D.sub.2 are each a radical of a diazo component selected from the group consisting of thiazolyl which is unsubstituted or substituted by nitro, methylsulphonyl, cyano, methyl, phenyl, chlorophenyl or nitrophenyl;
• pyridinyl or the N-methyl (methylsulfate) quaternary salt thereof;
• quinolinyl;
• pyrazolyl which is unsubstituted or substituted by phenyl, methoxyphenyl, cyano or nitrophenyl;
• indazolyl;
• 1,2,4-triazolyl which is unsubstituted or substituted by methyl, ethyl, phenyl or benzyl;
• benzthiazolyl which is unsubstituted or substituted by methyl, methoxy, ethoxy, chloro, cyano, thiacyanogen, nitro, carbethoxy, methylsulphonyl, or the N-methyl (methylsulfate) quaternary salt thereof;
• 1,3,4-thiadiazolyl which is unsubstituted or substituted by phenyl;
• 1,3,5-thiadiazolyl which is unsubstituted or substituted by methyl or phenyl;
• thienyl substituted by nitro or methylsulphonyl;
• isothiazolyl substituted by methyl;
• and phthalimidyl.