Monoazo hydroxy pyridone dyestuffs containing a methylene piperidino group

Azo dyestuff free from carboxylic acid or sulphonic acid groups selected from the group consisting of

• a. a dyestuff of the formula ##SPC10##
• wherein
• X is chlorine, bromine, iodine, --COOCH.sub.3, --COOC.sub.2 H.sub.5, --COCH.sub.3, --COC.sub.6 H.sub.5, --COC.sub.2 H.sub.5, cyano or trifluoromethyl,
• Y is hydrogen, methyl, ethyl, methoxy, ethoxy, chlorine, bromine, nitro, cyano, --COOCH.sub.3, --COOC.sub.2 H.sub.5, --COCH.sub.3, --COC.sub.2 H.sub.5, trifluoromethyl or alkylene forming with the phenyl ring 1-naphthyl,
• Z is ##SPC11##
• T is lower alkyl or phenyl,
• the ring A can be substituted with (X).sub.n alone or further substituted with lower alkyl or methoxy,
• m is 1 or 2 and
• n is 1 or 2 and
• b. a salt of the dyestuff of (a) with an acid selected from the group consisting of hydrochloric acid, sulfuric acid, phosphoric acid, sulphamic acid, boric acid, formic acid, acetic acid, propionic acid, citric acid, oxalic acid and mono-, di- and tri-chloracetic acid.