Fixing agents are important auxiliaries in the printing and dyeing industry. They are used to improve the color fastness of dyes on fabrics during wet treatment. On fabrics, they can form insoluble colored substances with dyes, thus improving the washing and perspiration fastness, and sometimes even the light fastness.
Commonly used fixing agents include cationic quaternary ammonium salts, such as hexadecylpyridine chloride and hexadecylpyridine bromide; amine-formaldehyde resin-type dicyandiamide-formaldehyde primary condensates (fixing agents Y, M); polyamine condensates (silk fixing agent LA); phenolic condensates (crosslinking fixing agent DE); crosslinking fixing agents (Indosol CR); reactive dye fixing agents KS; and phenolsulfonic acid-formaldehyde condensates used as fixing agents to replace tannins on nylon (polyamide) fabrics.
