Foam is the most common problem of high temperature and high pressure jet overflow dyeing. In the high-temperature and high-pressure jet overflow dyeing machine, the occurrence of foam is the result of high-energy turbulence caused by high-speed operation of the fabric and liquid circulation.
2. Wrinkles (wrinkles)
The wrinkles of polyester fabric dyed on the high temperature and high pressure jet overflow dyeing machine are often in the shape of chicken feet, which is due to the fact that the fabric is stacked in the stacking area for too long. If the fabric is folded, and this kind of fiber cooling through the secondary glass transition temperature, it is most likely to produce permanent wrinkles.
3. Uneven color
Reasons and prevention methods: If the temperature is too fast, the heating time should be reasonably determined; the heat preservation time is too short, and the heat preservation time should be reasonably determined; the circulation speed of the cloth is too slow, the nozzle pressure should be readjusted, and the nozzle gap and conical tube should be reselected to increase Cloth speed; dye adsorption is not uniform, dyeing materials should be selected reasonably. If disperse dyes with a large difference in dyeing rate are used in color matching, the amount of dispersant or dye should be increased appropriately; the cloth capacity far exceeds the standard capacity. The capacity should be moderate.
The production and hazards of oligomers: oligomers are low molecular weight condensation polymers produced during polymerization. In polyester products, most of the oligomers are cyclic compounds formed by three ethyl terephthalates; The polymer can dissolve in the dye bath and crystallize out of the solution at high temperature, and deposit on the surface of the machine or fabric when cooled, especially in the low liquid flow area. The oligomers deposited on the exchanger can restrict the liquid flow and reduce the heat exchange efficiency. Oligomers are deposited on the surface of the fibers, forming white spots or hoarfrost.
5. Cohesion of disperse dyes
The agglomeration of dyes can produce color spots on the fabric, reduce the dye uptake rate, and make the rubbing fastness worse.
6. Dye spots and color spots
Causes: dye coagulation; oligomers are produced in the dye bath.