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Factors Affecting Cationic Dyes

Jul 09, 2017

            cationic dyes on acrylic fiber affinity, dyeing due to rapid absorption and slow diffusion, easy to produce dyeing unevenness, and once the dyeing unevenness, it is difficult to extend the dyeing time to correct the method. When cationic dyes are dyed, the dyeing rate should be reduced appropriately to obtain uniform staining results. The factors affecting the dyeing rate of cationic dyes in addition to the types of acrylic fiber, there are the following:Cationic Dyes

            1. Ph Value: Dye bath add acid, can inhibit the dissociation of acidic groups in acrylic fiber, reduce the number of anion groups on the fibers, so that the Coulomb force between dye and fiber decreased, the dyeing rate decreased. The effect of ph value on the dyeing rate was more significant with the acrylic fiber, and the dyeing rate of acrylic fiber containing sulfonic acid was less affected by the ph value of the bath. The ph value of the dye bath should be controlled properly during dyeing. Cationic dyes are generally not alkali-resistant, dyeing the best ph value is generally 4-4.5, dye bath in the dark when the ph value can be higher, dyeing light should be at a lower ph value. The ph value of dye bath is generally regulated by acetic acid, which can reduce the ph value of bath and increase the solubility of dye. Sodium acetate is added to the bath and the ph value of the bath can be stabilized within the required range.Cationic Dyes

            Cationic Dye is the most commonly used slow dye agent, mostly cationic surfactants, such as 1227 surfactant (leveling agent Tan), 1631 surfactant (leveling agent Ⅳ State). Cationic slow dyeing agent has affinity to acrylic fiber. For smaller molecules and less affinity with the fiber cationic slow dye, because of the fast diffusion rate, the first to occupy the dye on the fiber, such as dye cation into the fiber, due to slow dye and fiber affinity is less than the affinity between dye and fiber, will gradually be replaced by dyes, so as to reduce the rate of dyeing. This type of slow dye dosage can not be too large, otherwise it will make the dye concentrated in the late dyeing, but cause dyeing unevenness. For the complex molecular structure, and fiber affinity with a larger cationic slow dye, dyeing with cationic dyes, thus reducing the dye rate of cationic dyes, but because the cationic slow dye in the fiber occupies a certain position of staining, so that the percentage of cationic dyes to reduce the dye. The higher the dosage of this kind of cationic slow dye, the more obvious the effect of slow dyeing, but the lighter the color of dye. Cationic slow dye dosage according to the nature and concentration of dyes used, the K-value of small dyes or dyed light-colored, cationic slow dye dosage is higher, to K-value of the dye or dye deep concentrated color, slow dye dosage is lower. Cationic slow dye to acrylic fiber also has a saturation value, and cationic dyes are also compatible with the value of the problem, the affinity of higher cationic dyes should use a higher affinity cationic slow dye agent. In the staining prescription, the dosage of cationic slow dye and cationic dye should not exceed the dyeing saturation value of the fiber.Cationic Dyes