Improvement of Dye Uptake of Indigo and Sulphur Dye in Denim Dyeing and Their Strength Percentage Evaluation in Different Concentration of Alkali Pretreatment
Abu Bakr Siddique, Rois Uddin Mahmud, Ahammod Babor Ali, Hosne Ara
Email: roisuddin@buft.edu.bd
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Abstract
Indigo dyes and Sulphur dyes are measured as very fashionable for clothes as they're having sensible overall fastness properties. Application of Indigo dyes and Sulphur dyes needs an awfully concentration of Caustic soda in the time of pretreatment process. The concentration of Caustic soda plays an important role in denim dyeing. Controlling the concentration of Caustic soda which is used in the pretreatment bath in denim dyeing, increased the dye uptake on warp yarn, good colorfastness, strength, lustrous and it ensured to achieve demanded color efficiency (depth of shed) with the use of lower dyestuffs compared to without controlling the concentration of Caustic soda in the time of pretreatment in denim dyeing. The optimum value was measured accurately because using data color spectrophotometer for measuring color strength and other test values were found from laboratory instrument of Nice Denim Mills Ltd. Scouring and dyeing process is carried out by Padding Mangle. Maximum dye uptake increase was observed at 270 g/l for Indigo Dark Shade, Indigo Light shade, Indigo Medium Shade, Sulfur Dark Shade, Sulfur Light shade. Also, these findings evidenced that tensile strength could be Decreased in this concentration. The optimum concentration of strength is 60g/l for light to medium shade and 90 g/l for dark shade.