High fastness heterocyclic azo disperse dyes bearing ester functions

Blue monoazo disperse dyes bearing carboxylic acid ester functions have been synthesised from thiophene diazo components in the search for colorants of high fastness and reduced environmental impact. The colour properties of the dyes in solution and on polyester, as well as the fastness of the dyes when applied to polyester, are examined and rationalised in terms of dye structure.