1. Acid dyes
Acid dyes are a type of water-soluble dyes with structural acidic groups that dye in acidic media. Most acid dyes contain sodium sulfonate, which is soluble in water and produces bright colors with a complete color spectrum. Acid dyes have a complete color spectrum and bright colors, and their light fastness and wet processing fastness vary greatly depending on the type of dye. Compared with direct dyes, acid dyes have simple structures and lack long conjugated double bonds and isohedral structures. Therefore, they lack directness to cellulose fibers and cannot be used for dyeing cellulose fibers. Different types of acid dyes have different dyeing properties due to their different molecular structures, and the dyeing methods used are different.
Usage: Mainly used for dyeing wool, silk and nylon, as well as leather, paper, ink, etc. Typically, no coloring force is exerted on cellulosic fibers.
2. Basic dyes
Basic dyes are also called salt-based dyes. Dyes that produce cationic dyes can dissociate in aqueous solutions and are classified as cationic dyes. It is characterized by bright color, strong fluorescence (mainly rose, yellow, orange, etc.), strong tinting power, small amount of dye, and rich color. It has poor color fastness and light fastness, but it has good fastness to acrylic fiber (polyene fiber). Basic dyes do not color cellulose fibers
Usage: Due to the poor color fastness and color fastness of fibers dyed with alkaline dyes, it is rarely used for dyeing fabrics. It is mainly used in the coloring and manufacturing of stationery and paper.