4 ways to improve the dyeing quality of overflow dyeing machines

1. The influence of the cloth capacity of the overflow dyeing machine

Overflow dyeing machines have an extra large nominal capacity, which is not suitable for any fabric. Therefore, in production, the actual capacity of the overflow dyeing machine needs to be determined according to the thickness and width of the fabric. For the same width of fabric, the thinner it is, the smaller the capacity. This is because if the light and thin fabrics are fed according to the nominal capacity, the length of the fabric will be too long, and the cycle period during dyeing will be long, which will easily cause the fabric to be knotted due to disorder in the dyeing room, resulting in fabric mottled.

2. Influence of winch speed and nozzle pressure

The fabric in the dyeing chamber is drawn into the nozzle by the winch. The nozzle is an annular outlet, and the dye liquor is sprayed from the gap of the nozzle. With the pressure of the nozzle, the dye liquor is sprayed on the rope-like fabric, changing the position of the fabric folded due to accumulation in the dyeing chamber. The speed of the fabric depends on the speed of the winch and nozzle pressure. In the temperature area where the fabric absorbs the dye, increasing the number of cycles of the fabric, that is, increasing the running speed of the fabric, is beneficial to the leveling of the fabric. When the liquid volume is constant, by increasing the flow rate of the dye liquor (that is, increasing the nozzle pressure), the cycle times of the dye liquor can be increased, the temperature in the dyeing machine and the uniformity of the dyestuff distribution can be improved, and the contact times between the dyestuff and the fabric can be increased, and the dyeing time can be shortened. shorten.

While increasing the fabric speed and increasing the number of dye liquor circulation, attention should be paid to the mutual cooperation between the winch speed and the nozzle pressure, otherwise it will directly affect the product quality. For example, if the speed of the winch is too slow and the nozzle pressure is too high, the cloth speed is greater than the speed of the winch, which is easy to cause fabric scratches; if the speed of the winch is too fast, exceeding the ability of the nozzle to pass through the fabric, the fabric will accumulate at the nozzle, Clogged nozzles will stop the dyeing machine and cause fabric mottled.

3. The influence of liquor ratio

The size of the liquor ratio not only affects the color of the fabric, but also affects the normal operation of the fabric in the dyeing machine. If the liquor ratio is too small, it is difficult for the fabric to run, and the winch cannot smoothly lift the fabric from the dyeing chamber, and the fabric runs slowly. If the bath ratio is too large, the fabric floats on the water surface, which is prone to disorder and knotting, causing the fabric to be dyed. On the other hand, if the bath ratio is too large, it will inevitably increase the amount of dyes and auxiliaries, and at the same time, it will increase the labor intensity of the batching operation. Therefore, the determination of the liquor ratio should be minimized on the premise of not affecting the operation of the fabric and ensuring the dyeing quality.

4. The influence of dyeing process

(1) The main factors affecting the dyeing quality of the overflow dyeing include dye use and addition method, dyeing temperature, type, dosage and addition method of salt and alkali agent, dyeing time, dye liquor bath ratio, etc. Among the above influencing factors, in addition to the addition method and bath ratio of dyes, salts and alkali agents, the other factors only affect the depth of fabric color, that is, the factors that affect the fixation rate of reactive dyes.

(2) For disperse dyes. When dyeing with disperse dyes at 90 °C, the heating rate can be larger, and above 90 °C, especially when it is close to 130 °C, the heating rate should be controlled to slowly approach the dyeing temperature to avoid uneven dyeing. The dyeing of disperse dyes is strongly affected by temperature, so in the temperature area where the dye is absorbed, increasing the number of cycles of the fabric and the dye liquor can make the dye and temperature distribution in the dyeing room uniform, which is beneficial to the leveling of the fabric.

After dyeing, start to lower the temperature slowly to avoid wrinkling of the fabric due to quenching. When the temperature drops to 100°C, rapid cooling can be used to reduce the temperature to 80°C, and then overflow cleaning is performed to further reduce the temperature in the dyeing room. If the discharge and water are carried out at a higher temperature, it is easy to form fabric creases and affect the dyeing quality.