colorant direct

Traductions

• anglais

  Date : 1984

  Définition

  A water-soluble organic dye, usually a sodium or calcium salt of an azo dye, which is adsorbed directly by the fibers of cotton, rayon, and other cellulosic materials.

  Note :

  Alkaline assistants are often added to promote efficient concentration, and detergents are commonly used as well. Such dyes may be introduced in colloidal form, but they will not be effective until a molecule dispersion is achieved (by increasing the temperature of the bath). The alkaline addition retards ionization of the dye molecules, which would prevent satisfactory dyeing action; only the undissociated molecule of the dye can be absorbed by the fibers.

  Termes :

  1. direct dye
  2. direct dyestuff

  Terme associé :

  1. direct colour