I. Pre-Operation Preparation
1. Equipment Inspection:
Confirm that the nozzle gap is uniform to avoid inconsistencies between fabric speed and dyeing volume.
Check that the buttons on the main pump, dye addition pump, and fabric delivery wheel are functioning correctly.
Set the program (such as temperature curve and time signal) to ensure it meets the requirements of the fabric being processed.
2. Chemical Preparation and Feeding:
Disperse dyes should first be pulped and stirred with cold water for 20-30 minutes, then diluted with 40-45℃ warm water.
Dispersants, ammonium sulfate, and other auxiliaries should be prepared as needed. For difficult-to-dissolve dyes, alcohol or a dispersing powder solution can be used to prepare the pulp.
Filter the dyeing process using a sieve; small particles should be re-dissolved and filtered again.
II. Dyeing Process Control
1. Temperature and Time:
Add acetic acid at approximately 40℃ to adjust the pH to 5-6, then add the dye and run for 10 minutes.
Dye uptake is slow at 50-60℃, accelerates above 80℃, and should not be too rapid between 80-130℃. 1. Cooling rate needs to be controlled to avoid wrinkles and "chicken claw" marks.
2. Liquor ratio and pressure:
The liquor ratio is usually 1:8-1:20, adjusted according to the equipment model and structure.
Nozzle pressure: The pressure can be higher when the fabric is loaded onto the machine, and reduced after normal operation; the thicker the fabric, the higher the pressure.
3. Color matching and leveling:
Add oligomer control agents to increase oligomer solubility or form a stable dispersion.
Use auxiliaries for post-treatment cleaning to remove deposited grease and dye.
III. Common Problem Handling
1. Color variation and color difference:
Dye not fully dissolved, excessively rapid heating, residual auxiliaries on the fabric, or uneven pH.
Solution: Pulp the dye with cold water, dissolve it in warm water, and add the following order: acid → auxiliaries → dye, controlling the heating rate.
2. Wrinkles (chicken claw marks):
Excessively rapid cooling, excessively long stacking time, improper nozzle design.
Solutions:
1. Solutions: Allow natural cooling (2℃/min to below 80℃), add anti-wrinkle agent (0.5g/L), avoid centrifugal dehydration.
2. Color Spots and Stains:
Dye not fully dissolved, fabric with sizing or oil stains, poor water quality.
Solutions: Filter dye, strengthen pretreatment, use low-foaming auxiliaries.
3. Safety and Maintenance:
1. Safe Operation:
Close the machine cover before dyeing and observe the fabric operation through the glass viewing window.
Check for abnormal sounds and phenomena in all parts of the machine.
2. Equipment Maintenance:
Clean the dyeing and rinsing tanks regularly to prevent dye deposition.
Strengthen the cleaning of the dyeing and rinsing tanks to prevent dye deposition.
