reactive dyes basic yellow

Cationic dyes is a kind of textile dyes, also known as alkaline Dyestuff and base. Cationic dyes are soluble in water and ionized in aqueous solution to produce positively charged colored ions. The cations of the dye can be combined with the acid group of the third monomer in the fabric to make the fiber dyeing.

The dyeing method and mechanism of cationic dyes

Cationic dye is the special dye of acrylonitrile fiber. The dyeing method is in the bathtub with weak acidity (pH value is about 4.5), with acetic acid and sodium acetate as buffer, in the presence of dielectric and appropriate additives, close to boiling dyeing. The dyeing mechanism can be divided into three steps:

(1) the dye cation in the dyeing bath is adsorbed on the surface of the fiber.

(2) the dye cation diffuses from the fiber surface to the interior.

(3) the dye cation is salt-bonded with the anion group contained in the fiber.

Under normal dyeing conditions, the last step of salt formation is an irreversible reaction, which can lead to high fastness and uneven dyeing. The first and last steps are fast, and the second step is slow, which determines the whole dyeing speed. Due to the large affinity between dyes and fibers, the bath temperature, pH value, electrolyte, and retarder should be strictly controlled to obtain the leveling effect.