The main reason is that polyester fiber dyeing is high temperature and high pressure. Although the decentralized dye molecules are small, they cannot guarantee that the dyes molecules enter the fiber during dyeing. Some decentralized dyes will be attached to the fiber surface. The reducing cleaning agent will not damage the dye molecules inside the fiber, which can improve the fastness and improve the color.
Polyester reduction and cleaning classification
1. Restore cleaning under alkaline conditions:
Soap washing agent+reducing agent (insurance powder or sulfur dioxide)+alkali (alkali or soda), but many domestic dyeing factories do not need soap washing agents.
Soap washing agent: Non -ion surface active agent, which is beneficial to the solubility of floating colors, disperse, and prevent re -shaped color. The commonly used flat plus O and tinyl phenol polyoxide ether NP10 effect is good.
Cattea surface active agent: Especially suitable for decentralized dyes adsorbed in spandex removal, significantly improved the coloring fastness of polyester/spandex chromatin (especially dark colors) (black nylon stains can reach level 4-5)
Restant: Compared to insurance powder, the advantages of sulfur dioxide crickets have a small smell, low dosage, and high persistence (high unit price)
When the insurance powder is used in the overflow and dyeing machine, most of the reducing cleaning fluid will be wasted by oxygen consumption by oxygen in the air during spraying, and the flat water washing can be used less.
Foreign manufacturers have tested that after the air in the overflow staining machine was rushed away in advance, it was found that the amount of insurance powder can be greatly reduced.
2. Restore and cleaning under acidic conditions:
Soap (same as above)+reducing agent (sulfonic acid)+acid (acetic acid)
The advantages of reducing cleaning under acidic conditions:
When the dyeing can be cooled to 80-90 ° C, the reducing and cleaning is performed without the discharge; relative to the insurance powder, the reducing agent used under acidic conditions is consumed by the air oxidation;
Restoration and cleaning are not universal under acidic conditions. In fact, compared to the alkaline restoration and cleaning process, the restore and cleaning under acidic conditions is more effective for even nitrogen decentralized dyes. Many dye factories use acidic reducing agents to find the effect of the effect when the effect is not alkaline.