INVESTIGATION OF INDIGO DYEING USING SODIUM BOROHYDRIDE AS REDUCING AGENT

Abstract

Indigo, one of the oldest dyes, has a very important role for the textile sector. It is primarily used to dye cotton clothes, and blue jeans and over one billion pairs of jeans around the world are dyed blue with indigo. Although Sodium Hydrosulfite (Na2S2O4) is used as a reducing agent in most indigo dyeing processes, it is environmentally unfavorable because of the resultant contaminated toxic wastewater. In addition, the color fastnesses of dyed samples using Na2S2O4 as reducing agent are not good enough. In the present paper sodium borohydride (NaBH4) were used as ecologically safe reduction systems for the indigo dyeing of cotton fabric. After dyeing processes, the color yield and fastnesses according to washing and rubbing were measured, and results were compared. It was found when NaBH4 was used as reducing agent instead of Na2S2O4, the color yield and the fastness properties of the dyed samples improved.