High Dye Fixation Pad-Steam Dyeing of Cotton Fabrics with Reactive Dyes Based on Hydrophobic Effect

Abstract

ABSTRACTTo enhance the dye fixation of pad-steam dyeing with reactive dyes, we used five kinds of dyes and water–ethanol dyeing medium to investigate the hydrophobic effect in dyeing process. The results indicated that the higher the molecule weight per water soluble group, i.e. the stronger dye hydrophobicity, the higher the dye fixation rate. When dyed with hydrophobic dye, both the alkali and steaming time can be reduced to realize the saving of chemicals and energy. For the more hydrophobic C.I. Reactive Orange 16 (RO16), the appropriate sodium carbonate concentration is 20 g/L, which is 10 g/L lower than the 30 g/L of C.I. Reactive Violet 5 (RV5). Similarly, RO16 just needed 2 min of steaming time to obtain the maximum K/S value, while RV5 needed 3 min. Enhancing the hydrophobicity of dyeing medium can also increase the dye fixation rates and K/S values. The K/S values and fixation rates of fabrics dyed with RV5 increased up mostly by 31.2% and 14% via using ethanol instead of 32 vol.% water in dyeing medium, respectively. All the dyed fabrics exhibit good color fastness.