Effect of the sulphonic group position on the properties of urea dyes

Azo dyes, analogues of C.I.Direct Red 23, have been prepared, using aniline sulphonic acids as diazo components and bis-ureido-6-(naphthol-1) as a coup ling component, and their colour properties have been examined, comparing t hem with those of a reference dye by the differential spectra method in aqu eous solutions as well as by the reflectance spectra analysis on dyed wool and cotton fabrics. It has been found that the dyes under investigation may be an alternative to the presently used conventional urea dyes. (C) 1999 E lsevier Science Ltd. All rights reserved.