How To Deal With The Dyeing Problem Of Elastic Band

The elastic band can generally be processed by continuous pad dyeing and scouring dyeing-grain method. The process flow is: blank belt → dyeing → steaming → washing → fixing → sizing → drying → setting. The production process of this process is short, and it can be completed with only 7-10rnin, due to the short processing time and the influence of other factors , There are often some quality problems, such as color difference, stain, spray, uneven dyeing, low color fastness, etc.

1. The tension problem

The tension of the webbing has a certain effect on the degree of color of the webbing. Under the same conditions of other processes, the color will be darker if the tension is high; the color will be lighter if the tension is small or no tension. When the webbing is under tension, the fiber is stretched, the specific surface area becomes larger, and the dye adsorption capacity is enhanced, so that the seven-dyeing rate of the webbing is increased, and the color is deepened. When it is necessary to dye dark colors, it can be properly considered under tension. Dye felt, but it should not be too large, otherwise it will affect the elasticity of the product.

Second, the choice of dyes

The raw materials of the elastic band are polyester, P11T-400, nylon, natural rubber, spandex, cotton yarn, etc. The dye compatibility is not easy to cause stains, uneven dyeing, poor color fastness and other problems.

3. Rolling residual rate

The elastic band is dyed by pad dyeing, and the webbing is dipped and dyed and then rolled by rolling. Make the dye evenly distributed. After steaming, the dyed ribbon is rolled and pressed. Most of the excess dye solution is rolled away, only a small part of the dye solution carried by the fabric is absorbed by the fibers, the remaining part is left in the gap between the yarns, and the other part is left in the capillary gap between the fibers. , Under the action of gravity, it is easy to flow. When drying, the moisture on the surface of the fabric evaporates, and the two parts of the dye solution move to the heated surface of the webbing, causing dye migration, and stains and uneven dyeing will occur. Therefore, the excess dye solution should be removed as much as possible. Experiments have proved that when the rolling residual rate is higher than 70%, stains are prone to appear, so the rolling rate JN should be controlled within 60%.

Fourth, the pH value

The pH value of the dye liquor has a significant effect on the dye uptake rate and the depth of the dye. The lower the pH value, the deeper the color of the webbing and the better washing fastness, which is conducive to the adsorption and dyeing of the dye. However, considering the level of dyeing, the pH value should generally be controlled at 4-6. For dyes with better levelling properties, the pH can be appropriately lower.

Five, steaming temperature

The steaming process can help the dye to diffuse inside the fiber, and the temperature and time of steaming should be appropriate, otherwise it will cause insufficient dye diffusion or increase energy consumption. Experiments show that for the depth of color, 105 steaming for 2 minutes is more appropriate, and then increasing the temperature and extending the time has little effect.

Six, additives

The main role of the auxiliary agent is to delay the adsorption rate of the dye, reduce the dye uptake rate, make the fiber surface uniformly adsorb the dye, and improve the uniformity of dyeing. When dyeing light colors, the amount of leveling agent should be higher, when dyeing dark colors, the amount of leveling agent used should be less, otherwise it will reduce the dye uptake percentage. For example, when dyeing nylon tape, in order to improve the uniformity of dyeing, a suitable leveling agent, such as DT, is often added to the dyeing solution. Pay attention to its compatibility with dyes when adding additives. The auxiliaries with larger molecules are used in weak acid dyes with larger molecules, which have stronger dyeing ability and better cover dyeing effect. Sometimes the fiber affinity auxiliary agent and the dye affinity auxiliary agent are mixed and used, and a better leveling and covering dyeing effect can also be obtained. Because the time for the ribbon to be immersed in the dye solution during padding is relatively short. Therefore, an appropriate wetting agent or penetrant is often added to the dye liquor to promote the uniformity of the dye and obtain a good leveling effect.

Seven, water quality

When dyeing with acid dyes, the influence of water quality is more prominent. Excessively hard water not only makes the color of the dyed product poorer, but also Cl- in the water has a greater impact on dyeing. The water used for making small samples should be the same as the production of large samples, and the water quality and pH value should be tested on the discharge day, and adjusted to the process requirements to avoid the difference in color and light.