Cotton-Nylon fabric/yarn dyeing
Cotton and Nylon blended fabrics may be dyed using the above process diagram. Machinery: (Cheese dyeing machine or Soft-flow machine)
- Set the dye bath with1.5 to 2.5 gpl acetic acid at room temperature.
- Add the total quantity of Glauber’s salt for reactive dyeing in two portions. This will function like a leveling agent for acid dyeing.
- Add the dyestuff mixture of acid and reactive dyes in two portions.
- Raise the temperature to 80°C @ 1°/minute.
- Hold at 80°C for 30 to 45 minutes according to the recipe/depth of nylon dyes (acid dyes).
- Then check the shade for nylon portion by carbonizing the cellulose in 70% Sulphuric acid.
- If not ok, make required additions and continue dyeing otherwise reduce the temperature to 60°C @ 2°/minute.
- At 60°C add alkali in two portions as mentioned above. Check pH. It should be 10.8 to 11.2.
- Continue dyeing for 45 to 90 minutes according to depth.
- Drop the bath.
- Cold wash twice for 10 minutes each.
- Neutralize with 1gpl of acetic acid at 40°C – Drain.
- Hot wash at 70°C – 10 minutes.
- I- Soaping with Sandopur RSK Liq – 2 gpl at 90°C
- II – Soaping with Sandopur RSK Liq – 1 gpl at 90°C
- Hot wash at 70°C
- Cold wash – twice for 10 minutes each.
- Acid wash with 1 gpl acetic acid at cold.
- Unload or take it for finishing.
Few suggestions for continuous dyeing are:
- Continuous Dyeing of Nylon and cotton blends may be done using disperse and reactive dyes in the same way we do for polyester and cotton. Thermosolling may be done at 80 to 90°C instead of 135 to 150°C. A bottleneck with disperse dyeing is, you can produce only light and medium shades only. With disperse dyestuff you may not get proper yield and washing fastness.
- With Clariant there is a dyestuff called ‘Forosols’ that can be used for dyeing both cotton and polyester for solid shades. You can make a lab trial in consultation with Clariant people and then finalize your process for continuous dyeing.