1. It is easier to dye nylon with disperse dyes using alkali agents to reduce the color, but the shade changes greatly, and the darkening is serious.
2. For dyeing nylon with neutral dyes, soda ash treatment has almost no color reduction ability, and the shade changes, caustic soda has the color reduction ability, and the higher the concentration, the greater the color reduction ability, and the greater the shade change.
3. When dyeing nylon with acid dyes, soda ash has almost no color reduction ability, but the shade change is small; caustic soda has a slight color reduction ability, but the shade change is serious.
It can be seen that the color reduction of nylon dyed products with alkali agents is either low in color reduction rate or serious color change (especially darkening). This brings great difficulty to the lower path of color repair, and even the original color light cannot be repaired.
Therefore, when the dyed fabric of nylon must undergo color reduction (lightening) treatment, the color stripping agent-caustic soda method can only be used for proper color stripping treatment as needed, and then proofing and re-dyeing (color correction).