I. Basis for Setting Dyeing Time
1. Dye Type:
Reactive dyes: Generally, dyeing time should be controlled between 30-60 minutes.
Disperse dyes: Due to the need for high temperature (120-130℃), a time of 30-60 minutes is also recommended.
Highly reactive dyes: Dyeing at lower temperatures allows for a shorter time, but it is essential to ensure sufficient dye uptake.
2. Fabric Characteristics:
Fabrics with good absorbency (e.g., cotton, viscose): The time can be slightly shorter to avoid over-dyeing.
Fabrics with poor absorbency (e.g., synthetic fibers): The time needs to be extended to ensure even dye penetration.
3. Dyeing Depth:
Light colors: The time can be shortened to 30-40 minutes.
Dark colors: The time needs to be extended to 50-60 minutes to ensure rich color.
II. Operational Precautions
1. Dyeing Time Control:
The time for the fabric to be rolled from one roll to another should not exceed 15 minutes; otherwise, the color difference between the beginning and end will be very obvious.
It is recommended to use a one-bath, two-step method: first, dye the fabric in 4-6 passes, then fix it in 4-6 passes, and finally wash and soap it.
2. Temperature and Time Coordination:
Reactive dyes: Temperature 60-90℃, Time 30-60 minutes.
Disperse dyes: Temperature 120-130℃, Time 30-60 minutes.
3. Dye Solution pH Value:
The pH value of the dye solution needs to be controlled between 4.5 and 6.5 to ensure the stability of the dye performance.
III. Common Problem Solutions
Color Difference Between Beginning and End: Check if the dyeing time exceeds 15 minutes, or if the dye solution concentration is uniform.
Uneven Dyeing: Adjust the fabric travel speed to ensure sufficient dye penetration.
