Views:3 Author:Site Editor Publish Time: 2017-05-05 Origin:Site
In addition to individual processes,we can use soft water in most of the processes in printing and dyeing industry, so chelating agent can be added to chelate the metal ions in water to achieve the purpose of softening water.
When sizing, some textile mills may add the heavy metal compounds for preservation. The addition of these compounds will against the desizing of enzyme. Adding chelating agent can chelate these metal ions. In addition, when desizing, the application of chelating agent can make the slurry more easier to puff, separate them from the fiber and dispersed into colloidal and then removed. At the same time, the strong dispersibility of chelating agent can prevent the impurities and slurry deposited again on the fiber , so that the base fabric will be purer, the desizing will be more complete, and the equipment will be cleaner.
3. Boiling off
Adding chelating agent in the scouring process can chelate and disperse the Mg2+ and Ca2+ in scouring liquid. It is conducive to the removal of pectin and may prevent the insoluble calcium, magnesium salt deposited on the fabric. As a result, we can improve capillarity and eliminate calcium spot. Then the effect of scouring will be promoted and the levelling property will be improved.
The metal ions such as Fe2 +, Fe3 +, Mn2 +, Cu2 +, Ni2 + brought by the equipment piping and aqueous solution will accelerate the decomposition of hydrogen peroxide, resulting in the local over-oxidation of the textile during the bleaching process and then its strong ability will decline, and even produce holes. Adding chelating agent in the textile bleaching, which can effectively block metal ions, indirectly control the rate of hydrogen peroxide decomposition, and prevent textile damage. Chelating agents used for washing after bleaching can make the impurities remove from the fiber surface. If we often use odium silicate as hydrogen peroxide bleaching stabilizer when using hydrogen peroxide for bleaching, it will produce silicon scale after a long period. If adding chelating agent, it can prevent the deposition of silicate crystals in the equipment, long-term use can also clear the hard scale on the equipment.
Chelating agent has the ability of dispersion, complexation, and electrostatic repulsion. It can help the dye dissolve, increase its diffusion rate, so that the dye can spread fully and evenly in a shorter period of time, and dissolved in the dye, and then dye the fiber. During the dyeing process, the presence of metal ions such as Ca2 +, Mg2 +, Cu2 +, Fe3 +, Al3 + in the dyeing bath will denature the dye and affect the dyeing properties. And the addition of the chelating agent can prevent its action, it will complex metal ions and impurities in the dye liquor. Then it will form stable complexes, reduce the association of dyes, avoid the occurrence of stains and other defects, and make an indirect leveling effect.