Generally, the factory’s water will have calcium, magnesium, iron ion, and these particle impurities will be deposited on the fiber surface. Chelating agents chelate metal ions, and it is widely used in the dyeing and finishing processes. For example in desizing, we remove copper and iron ions, in order to reduce its impact on the enzyme desizing agent. Next, in scouring of cotton, we prevent precipitation of calcium soaps, and it is beneficial to remove pectin, improving whiteness and touching feeling.
Besides, in hydrogen peroxide bleaching, we prevent heavy metal ion on hydrogen peroxide of catalytic decomposition. In addition, in dyeing, we have to prevent hard water calcium, magnesium ions and heavy metal ions from affecting the color, especially when we use the metal chelating dyes. It’s very important for us to choose the stable chelating agent because we don’t want the iron ion to affect the coloring light, and also we don’t want to detach the iron ion in the dye.