Definition of Cationic Dyes
by : Rahul Sharma
CATIONIC DYES:
Cationic dyes are dyes that can be dissociated into positively charged ions in aqueous solution. They can interact with the negative groups on the fiber molecules to from salts, which can be further firmly attached to the fibers, therby staining the fibers. Cationic dyes have been successfully developed based on alkaline dyes. The stained principle of cationic dyes is to dye the fibers by combining their cations with acidic groups in the third monmer of acrylon, thereby resulting in high fastness. Cationic dyes are originally used in the dyeing of silk, leather, paper and cotton, as well as the production of ink and copying paper in the office supplies industry. With the development of synthetic fibers, the importance of cationic dyes for dyeing textiles has greatly increased.
There are many types of cationic dyes such as azo dyes, triarylmethane dyes, anthraquinone dyes, and heterocyclic compounds. The commonly used is the cationic portion in the dyes having an onium group to form salt with hydrochloric acid (or sulfuric acid).
Cationic dye is now mostly applied to the dyeing of the polyester fiber and acrylic fiber.
