The application of fixing agents in dyeing

The application of fixing agents in dyeing

Some dyes can produce vivid colors during the dyeing process, their water-soluble groups may lead to poor wet processing fastness and serious fading and staining phenomena. This not only makes the appearance of the textile itself old-fashioned but also causes the dye to fall off and stain white or other colored fibers, resulting in staining or color matching phenomena. Direct dyes and acid dyes are prone to such problems.

Furthermore, although reactive dyes can form covalent bonds with cellulose fibers, insufficient washing of hydrolyzed dyes or unbound dyes during dyeing can lead to a decrease in wet processing fastness. Reactive dyes that have already formed covalent bonds with fibers may also undergo decomposition or bond cleavage under acidic or alkaline conditions, resulting in poor chlorine fastness, sweat fastness, and light fastness.

The use of fixing agents can effectively improve wet processing fastness and prevent the above-mentioned problems.

The principle of fixation:

Firstly, the dyeing mechanism and the color fastness of the dye on different fibers are different. Therefore, the fixation mechanism and application of the fixing agent used are also different.

The cationic groups such as quaternary ammonium salt or tertiary amine salt in the fixing agent molecule are utilized to combine with the anionic groups in the ionic dye structure to form an insoluble color block on the fiber, thereby improving the color fastness of the dye on the fabric.

The solubility of dyes is reduced by crosslinking the hydroxyl groups in cellulose molecules with the reactive groups of dye molecules, utilizing the reactive groups in color-fixing agent molecules.

One method to improve the color fastness of fabrics is to utilize the film-forming properties of a fixing agent. After treatment with the fixing agent, the fabric undergoes self-crosslinking of the reactive groups on the fixing agent molecules during high-temperature drying, resulting in the formation of a protective film with a certain level of strength on the surface of the fabric and fibers. This film encapsulates the dye on the fibers, making it less likely to detach.

"What are good fixing agents?

In general, good fixing agents should have the following properties: strong fixing ability, which can significantly improve the related color fastness of the fabric; wide adaptability to dyes, with a small impact of dye structure on fixing effect; strong affinity with fibers, with high exhaustion rate in fixing rate; no color change of fabric after fixing with fixing agents; while improving color fastness (such as washing fastness), other color fastness (such as light fastness) should not be reduced; no impact on the feel of the fabric and no significant reduction of the fabric strength."

Recommended high-quality color fixing agent product.

• Cotton Fixing Agent CY-211H (General)

• Cotton Fixing Agent CY-211HB (Direct Dye)

• Formaldehyde-free Color Fixative Agent CY-2802 (Environmental protection)