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, disperse dyeing is done. In the carrier method, more than 85°c is not needed. Here, the carrier helps the dyes to disperse easily in presence of the dispersing agent.
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Recipe
Functions of the Chemicals Required
Dispersing agent: It is used in polyester dyeing to distribute the dye molecules in dye molecules into the substrate.
Sequestering agent: A sequestering agent is a substance that suppresses as property or reaction of metal ions without the removal of that metal from the system.
Leveling agent: Levelling agent tends to slow down the dye uptake on the fibers, helping to produce a more uniform color in the textile fiber.
Acetic acid: Its function is to control the pH and neutralize the solution of the dye bath.
Carrier: It assists in dispersing dyes to enter the polyester polymer. It swells the polyester fiber and increases the polymer space and lets the dye molecular enter into the fiber easily. Caustic soda: Neutralizes acidic materials, and saponifies glycerides.
Hydrose: It is used as a reducing agent. It turns the insoluble dye to produce a weak acidic leuco form. This helps in the reduction clearing of the surface of the fabric.
Recipe Calculation
Here, M:L = 1:40
Sample weight: 5 gm
Total liquor : 5 ✕ 40 = 200 ml
Disperse blue;
100 gm fabric needed 2 gm of dye
So, 5 gm fabric needed (2 ✕ 5) / 100 = 0.1 gm of dye
Chemicals = (g/L × Total liquor) / 1000
Dispersing agent = (2 ✕ 200) / 1000 = 0.4 gm
Acetic acid = (1 ✕ 200) / 1000 = 0.2 ml
Carrier = (2 ✕ 200) / 1000 = 0.4 ml
Levelling agent = (1 ✕ 200) / 1000 = 0.2 ml
Sequestering agent = 0.2 gm
Total = (0.2 + 0.4 + 0.2) = 0.8 ml
Freshwater = (200 – 0.8) = 199.2 ml
Shade Attachment
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| Dispersed Dyed Polyester Sample ©Textile Pad |
Dyeing Curve
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| Polyester 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 carrier increases polymer space and helps in trapping the dyes in the molecules of the fabric.