Dye-fixing agent is widely used in the dyeing, I will introduction the eight functions of dye-fixing agent.
1. The reactive groups in dye-fixing agent will crosslink with the reactive groups of dye and hydroxy of fiber, achieving the purposes of dye-fixing.

2. It will produce insoluble color lake, closing the soluble group and the dye on fabric will not drip off, reaching the purpose of wet fastness. But this kind of color-fixing is easy to cause the color change and the decrease of light fastness.

3. The molecular attraction of dye fixing agent and fiber will increase the fixing strength of the dye-fixing agent,  thus, the fastness will increase.

4. Produce net film covering on the fabric and prevent the dye from dropping.

5. Introduce ultraviolet light absorber into the dye-fixing agent molecule, the Ultraviolet absorption groups will absorb the ultraviolet ray in sunshine, and prevent the damage to ultraviolet ray on dyeing structure, thus it will improve the light fastness.

6. The use of some substance’s chlorine resistance or oxygen suction property, prevent the attack of active chlorine on activated dyes. Thus it will improve the resistance to chlorine leaching fastness and fastness to chlorine bleaching.

7. The acid absorbing ability of dye-fixing agent will neutral the acidic chemicals  in the perspiration. And prevent the broken of  the activate dyeing covalence bond between active dye and fiber. Thus, the reach the purpose of perspiration fastness.

8. The smoothing agent in the dye-fixing agent will decrease the friction coefficient of fiber surface, thus, it will improve fabric’s crockfastness