Redox systems based on ammonium persulphate as oxidant along with ethylene glycol, urea, thiourea, glucose or formaldehyde as reluctant were incorporated in the printing formulations of wool to improve its printability with anionic dyes, i.e. acid, reactive and direct dyes. It was found that for a given set of printing conditions, ethylene glycol/ammonium persulphate redox system proves to be the most effective one. Increasing the concentration of this redox system up to (0.025/0.050 mol/k), raising the steam fixation temperature up to 130°C for 15 min, as well as increasing acid dye concentration bring about a significant increase in the depth of wool prints. The depth of shade as well as the extent of dye fixation enhanced significantly in presence of this redox system, irrespective of the acid dye used. Extent of printability, dye fixation as well as fastness properties of wool prints governed by the structural aspects of different classes of the anionic dyes under investigation. It is postulated that incorporation of the redox system in the printing formulation generates free radicals, creates additional printing sites on the wool matrix as well as converts the dye to its free radical form, which in turn, brings about covalent fixation in addition to ionic and physical links
By: N.A.Ibrahim, M.R.El Zairy*, A.R.El-Gamal*, and S.A. Tolba* National Research Centre, Textile Resea
Submit Date: 6/7/2010 18:00