Theory
Disperse dyes are non-ionic in nature and insoluble in water. For hydrolyzing it, needed a high temperature. There are more crystalline regions in polyester. In acidic conditions, dyes are simply mechanically trapped in the fiber or fabric structure during dyeing. Thus, dispersed dyeing is done.
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Recipe
Recipe Calculation
Sample weight: 2 gm
Total liquor : 2 ✕ 20 = 40 ml
Dye = (Shade % ✕ Sample wt.) / (Stock solution%)
Disperse red = (0.60 ✕ 2) / 1% = 1.2 ml
Disperse blue = (0.40 ✕ 2) / 1% = 0.8 ml
Disperse yellow = (0.80 ✕ 2) / 1% = 1.6 ml
Chemicals = (g/L ✕ Total liquor) / 1000
Dispersing agent = (1 ✕ 40) / 1000 = 0.04 gm
Acetic acid = (1 ✕ 40) / 1000 = 0.04 ml
Total = (1.2 + 0.8 + 1.6 + 0.04) = 3.64 ml
Freshwater = ( 200 - 3.64) = 36.36 ml
Functions of the Chemicals Required
Dispersing agent: It is used in polyester dyeing to distribute the dye molecules in dye molecules into the substrate.
Acetic acid: Its function is to control the pH and neutralize the solution of the dye bath.
Shade Attachment
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| Polyester Part Dyed Sample ©Textile Pad |
Dyeing Curve
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| Polyester Part Dyeing Curve ©Textile Pad |
Conclusion
The addition of dispersing agents increases the dye solubility and accelerates the dye diffusion into the swelled fiber structure. The high temperature helps in breaking the crystalline regions of the polyester fabric.