Direct Dyes

Description

Direct dyes are a class of water-soluble dyes that can be directly applied to fibers from an aqueous solution without the need for a mordant or additional chemical treatment. They are typically anionic dyes and have good affinity for cellulose fibers like cotton and other cellulosic materials. The dye molecules adsorb onto the fiber through hydrogen bonding and van der Waals forces.

Color Characteristics

Direct Yellow 5GII
Direct Orange SE
Direct Hellio B
Direct Brown MR
Direct Vioelt MB
Direct Green PLS
Direct Bordeaux BW
Direct Black 22
Direct Congo Red
Direct Yellow 6
Direct Yellow 99
Direct Orange TGLL
Direct Scarlet Red 4BS
Direct Red 81
Direct Red 239
Direct Black BT
Direct Red 227
Direct Chrysophenine
Direct Black E
Direct Viscose Orange
Direct Red 31
Direct Blue RLL
Direct Blue 86
Direct Sky Blue FF

Key Characteristics

  • Solubility: Soluble in water, which allows easy dyeing without requiring additional chemicals.
  • Affinity:High affinity towards cellulosic fibers like cotton, viscose, and linen.
  • Application: Applied in neutral to slightly alkaline bath conditions.
  • Fixation: Adsorbed physically on the fiber surface, relying mostly on hydrogen bonding and van der Waals forces; no covalent bonding.
  • Dyeing method:Usually applied by exhaust dyeing, often at temperatures between 60–95°C.
  • CostGenerally economical and easy to use for large-scale dyeing.
  • MigrationGood migration properties in dye baths allow even dyeing.
  • FastnessModerate fastness properties; improvements possible by after-treatments such as cationic fixing agents.

Applications

Textile dyeing

Paper industry

Leather

Printing inks

Crafts