1. Pre-treatment Process
Desizing and Scouring: Treat with 3–5 g/L NaOH and 1–2 g/L scouring agent at 80°C for 20 minutes to remove sizing agents and oil stains from the fabric surface.
Washing: Rinse twice with hot water at 60°C to ensure a neutral pH on the fabric surface, preventing uneven dyeing (color blotches) in subsequent steps.
2. Core Dyeing Process
Material Loading: Load fabric to within 80% of the machine's capacity; secure the fabric roll to ensure full submersion.
Dye Liquor Preparation: Based on fabric weight, add 1–5% disperse dye and 0.5–1 g/L dispersing agent; adjust pH to 4.5–5.5 using acetic acid.
Graduated Heating: Begin circulation at 40°C for 10 minutes; heat at 1–2°C/min to 90°C, then at 0.5°C/min to 130°C; hold temperature for 30–45 minutes while maintaining a pressure of 0.2–0.3 MPa throughout.
3. Post-treatment Process
Reduction Clearing: Treat with 2 g/L sodium hydrosulfite and 1 g/L caustic soda at 80°C for 15 minutes to thoroughly remove unfixed surface dye.
Graduated Cooling: Cool slowly to below 50°C before draining the liquor to avoid creases caused by rapid cooling.
Washing and Neutralization: Counter-current rinse with warm water at 40°C; neutralize with acid to achieve a neutral pH; ensure final rinse water conductivity is ≤10 μS/cm.
4. Finishing Process
Centrifugal dewatering to a moisture content of 30%–35%; hot-air drying at 80–100°C; control final residual moisture to ≤8%.
