Types of dyeing

Classification of dyes:

• Vat dyes
• Acid dyes
• Basic dyes
  
• Direct dyes
  
• Reactive dyes
• Disperse dyes
• Azoic dyes/ Naphthol dyes
  
• Sulfur dyes

Vat dyes: Vat dyes are insoluble dye and widely used for cellulose fibers can be used for protein and nylon fibers.This dyes produce good color rang but large amount of dyes are required for deep shade. Vat dyes have excellent fastness to washing and very good fastness to crocking.

Acid dyes: Dyes of organic acid that are attract and attached the color to the fiber. This dyes are available in the form of salt, water soluble and are applied in acid medium. Mainly used for wool and silk; acrylic, nylon and spandex.Bright colors tend to bleed; some colors have good fastness to sunlight, dry clean and crocking but some colors have poor fastness to washing.

Basic dyes: Basic dyes are water soluble and mainly used for acrylic/ mod acrylic. This can be effective for wool and silk but poor fastness properties; also being used for nylon, polyester and cotton. Basic dyes produce complete range of bright colors and good color fastness light, washing perspiration and crocking for acrylic and mod acrylic but very poor fastness to washing and light on cotton,wool and silk.

Direct dyes: Direct dyes are water soluble and least expansive. This dyes used only for cellulose fibers. This dyes have good color fastness to perspiration/ dry clean but poor fastness to washing and crocking.

Reactive dyes: This is water soluble anionic dyes. Primarily used for cotton and other cellulose fibers; wool, silk. This dyes are available in complete range of colors including very bright colors and very good fastness to washing and light; good fastness to dry clean, perspiration and crocking but poor fastness to chlorine bleaching.

Disperse dyes: This dyes are ex trimly low soluble in water. Dyeing is carried out high temperature/pressure and can be used in heat transfer printing. Disperse dyes can be used for nylon/ acrylic and other synthetic fibers. This dyes have good- excellent fastness to perspiration, crocking and dry cleaning and good fastness to light and washing.

Azoic dyes/ Naphthol dyes:This is insoluble in water; primarily used for cellulose fibers but some times also used of polyester to produce black shades. Azoic dyes lack green and bright blue colors. This dyes have good fastness to washing and dry cleaning but poor fastness to light. Dark colors have poor fastness to crocking . dyeing process is complexity and time consuming.

Sulfur dyes: Sulfur dyes are water soluble and widely used for celluloses. This dye produces a complete range of colors in dull shades but poor light fastness in pastel shades. Sulfur dyes have good fastness to light, washing, dry cleaning and perspiration but poor fastness to chlorine bleaching.