1. Utilize the cationic group in the molecule of the formaldehyde-free fixing agent and the anionic group in the dye molecule to form an ionic bond to form a lake and deposit on the fiber, thereby reducing the water solubility of the dye and improving the soaping and white cloth of the dyed fabric Color fastness, the more cationic groups in the fixing agent molecule, the stronger the cationicity, the better the soaping fastness of the fabric after fixing.

2. Use the reactive groups in the fixing agent molecules to react with the reactive groups on the dye molecules and the reactive groups on the fiber, thereby reducing the water solubility of the dye, improving the binding force of the dye and the fiber, and achieving an increase The purpose of the wet processing fastness of dyed fabrics (such as soaping, white cloth staining, wet rubbing, wet ironing fastness).

3. Utilize the film-forming properties of the fixing agent to form a firm film to firmly coat the dye on the surface of the fiber, so as to achieve the purpose of improving the fastness of dyed fabrics, especially the rubbing fastness.

4. Use the intermolecular attraction between the fixing agent and the fiber and dye to increase the fixing strength of the fixing agent, thereby improving the color fastness.

5. Use the smoothing agent in the fixing agent to make the fiber surface smooth and soft, thereby improving the rubbing fastness of the dyed fabric.