Preparation, properties and environment-friendly dyeing application of reactive brilliant blue dye based on triphenodioxazine chromophore

By modifying the structure of the reactive group, the dye VS-GN containing two sulphatoethylsulphone groups based on the triphenodioxazine chromophore was developed. The solubility of VS-GN reached 300 g/L at 25°C. The substantivity and reactivity were 49.3% and 53.1%, respectively. VS-GN showed excellent stability under salt–alkali and alkali stress. Environmentally friendly dyeing methods, including low liquor ratio and cold pad-batch dyeing techniques, were successfully applied for the reactive dye VS-GN. VS-GN completed the exhaust dyeing process at 60°C, and its fixation on cotton fabric was 85.9% at a dye concentration of 2.0% when the liquor ratio was 1:6 and the concentration of Na2CO3 and Na2SO4 were 10 and 80 g/L, respectively. The fixation of the dye VS-GN on cotton fabric using the cold pad-batch dyeing method (10 mL/L of NaOH, 38 oBe’, 20 g/L of Na2CO3, and a batching time of 8 h) was 86.4% at a dye concentration of 20 g/L, which was 27.4% higher than that of conventional reactive brilliant blue KE-GN. The results of the levelness of the dyed cotton fabrics showed that the dyed cotton fabric dyed with VS-GN exhibited a good dyeing level with a low value of Δ E (<0.4). The results of color fastness at a 1/1 standard depth showed that the light fastness of the dyed cotton was grade 4. The dry and wet rubbing fastnesses of the dyed cotton fabric were grades 4–5 and 2–3 or 3, respectively. The washing fastness of the dyed cotton fabric was grade 4 or 4–5.