PH Of The Dye Bath For Cationic Dyes

Adding acid to the dyeing bath can inhibit the dissociation of acidic groups in acrylic, reduce the number of anion groups on the fiber, reduce the coulomb gravity between the dye and the fiber, and reduce the dyeing rate. The effect of pH value on dyeing rate was more significant for carboxylic acid-containing acrylic fibers, and the influence of sulfonic acid-containing acrylic fibers was less affected by the pH value of the dyeing bath. When dyeing, the pH value of the dyeing bath should be reasonably controlled. Cationic dyes are generally not resistant to alkali, the optimal pH value of dyeing is generally 4-4.5, the pH value of the dyeing bath can be higher when dyeing dark colors, and the dyeing of light colors should be carried out at a lower pH value. The pH of the dyeing bath is generally adjusted with acetic acid, which can not only reduce the pH value of the dyeing bath, but also improve the solubility of the dye. The addition of sodium acetate to the dyeing bath at the same time stabilizes the pH value of the dyeing bath within the required range.
3. Electrolytes
Adding electrolytes, such as yuan powder and salt, to the dyeing bath can reduce the dyeing rate of cationic dyes and have a slow dyeing effect. The electrolyte has no obvious dyeing effect on dyes with K value 1~1.5, and has a slow dyeing effect on dyes with K value 3~5. The slow staining effect of the electrolyte decreases with the increase of staining temperature. When dyeing light color, the amount of electrolyte can be higher, about 5% ~ 10% (O.W.F.), and can not be added when dyeing dark color.