Question

The Pad - Dry - Cure process is followed in \(\underline{\hspace{2cm}}\)

• A. Reactive Dyeing
• B. Pigment dyeing
• C. Vat dyeing
• D. Direct dyeing

Hint:

Associate the fixation step with the dyeing method: - Pigment \(\rightarrow\) Cure (High heat to set the binder). - Reactive \(\rightarrow\) Alkali + Time (Pad-Batch) or Steam (Pad-Steam). - Vat \(\rightarrow\) Reduce, Oxidize. - Disperse \(\rightarrow\) Thermofixation (High heat to make dye diffuse into fiber).

Answer 1

The Correct Option is B

Step 1: Understand the "Pad - Dry - Cure" sequence. 
- Pad: The fabric is padded (impregnated) with a chemical solution, in this case, a mix of pigment, binder, and other auxiliaries. 
- Dry: The fabric is dried to remove water. 
- Cure: The fabric is heated to a high temperature (e.g., 150-180°C). This step is crucial for a chemical reaction to occur. 
 

Step 2: Analyze which dyeing method requires this sequence. 
- Reactive Dyeing: A common method for reactive dyes is Pad-Dry-Pad-Steam, where the final fixation happens in steam. Another is Pad-Batch, where it's stored at room temperature. A "cure" step is less common than for pigments. 
- Pigment dyeing/printing: This process relies on a binder that must be polymerized and cross-linked to fix the insoluble pigment onto the fiber. This polymerization is achieved by heating at high temperatures, which is the "Cure" step. This sequence is the standard method for pigment application. 
- Vat dyeing: This involves padding the dye, then a chemical padding for reduction, followed by steaming and oxidation. It does not use a high-temperature "cure" step for fixation. 
- Direct dyeing: This is an exhaustion process, often followed by drying. It doesn't involve a curing step for fixation. 

Conclusion: The high-temperature "Cure" step is characteristic of cross-linking the binder in pigment dyeing/printing.