Disazo dyestuff sulphuric acid ester

A disazo dyestuff which, in the form of the free acid corresponds to the formula ##STR21## wherein R.sub.1 denotes hydrogen, alkyl, alkyl substituted by fluorine, chlorine, cyano, hydroxyl, C.sub.1 -C.sub.4 -alkoxy, phenoxy, C.sub.1 -C.sub.4 -alkylcarbonyloxy or phenyl, phenyl substituted by C.sub.1 -C.sub.4 -alkoxy, chlorine, cyano, nitro or C.sub.1 -C.sub.4 -alkyl or cyclohexyl,

• R.sub.2 denotes chlorine, bromine, alkoxy, alkoxy substituted by fluorine, chlorine, cyano, hydroxyl, C.sub.1 -C.sub.4 -alkoxy, phenoxy, C.sub.1 -C.sub.4 -alkylcarbonyloxy or phenyl, alkyl, alkyl substituted by fluorine, chlorine, cyano, hydroxyl, C.sub.1 -C.sub.4 -alkoxy, phenoxy, C.sub.1 -C.sub.4 -alkylcarbonyloxy or phenyl, acetylamino or benzoylamino,
• R.sub.3 and R.sub.4 denote hydrogen, chlorine, bromine, alkoxy or alkyl, which alkoxy or alkyl can be unsubstituted or is substituted by fluorine, chlorine, cyano, hydroxyl, C.sub.1 -C.sub.4 -alkoxy, phenoxy, C.sub.1 -C.sub.4 -alkylcarbonyloxy or phenyl,
• R.sub.5 and R.sub.6 denote hydrogen, alkyl, alkoxy, chlorine or phenyl, which alkyl or alkoxy can be unsubstituted or is substituted by fluorine, chlorine, cyano, hydroxyl, C.sub.1 -C.sub.4 -alkoxy, phenoxy, C.sub.1 -C.sub.4 -alkylcarbonyloxy or phenyl and which phenyl can be substituted by C.sub.1 -C.sub.4 alkoxy, chlorine, cyano, nitro or C.sub.1 -C.sub.4 -alkyl,
• R.sub.7 denotes alkyl, alkylcarbonyl, phenylcarbonyl, alkylsulphonyl or phenylsulphonyl, which alkyl can be unsubstituted or is substituted by fluorine, chlorine, cyano, hydroxyl, C.sub.1 -C.sub.4 -alkoxy, phenoxy, C.sub.1 -C.sub.4 -alkylcarbonyloxy or phenyl and which phenyl can be substituted by C.sub.1 -C.sub.4 alkoxy, chlorine, cyano, nitro or C.sub.1 -C.sub.4 -alkyl,
• X denotes branched or unbranched C.sub.2 -C.sub.4 -alkylene,
• B denotes 1,4-phenylene, 1,4-naphthylene or tetrahydro-1,4-naphthylene and
• m denotes a number from 0-2.