Nylon yarn filament dyeing - tips

Nylon Yarn Dyeing:

• Like polyester fiber, (polyamide) nylon also requires to be heat set prior to any wet processing. Nylon can be best heat set in aqueous water bath at about 120°C for half an hour with a dispersing agent like Ekaline FI. This treatment should be followed by hot and cold washes. Then dry the yarn and rewind it on parallel winding machine.

• Pretreatment & Dyeing:

1. Sodium Acetate = 1%
2. Acetic acid = 1%
3. Glauber salt = 10 %
Run at 50°C for one cycle. Now add the dissolved dyestuff at the same temperature. Run at 75° for 10 minutes and raise the temp to 95°C and continue dyeing; add a leveling agent such as Lyogen SE at this temp (for dark shades 1% and for light shades up to 4% or as recommended by the manufacturer).

• After treatment:

1. After thorough hot and cold washes, a fixing treatment is required for dark and medium shades. There are products like Lyogen PA liquid are available for this purpose and the user should follow the instructions of the manufacturer.
2. Finishing of nylon yarn can be made using some anti-static agent in the final bath.
3. Hydro extract, dry and rewind.

Ref:
Textile Processing Guide