General Theory of Dyeing

The General Theory of Dyeing

Dyeing is the process of coloring textile materials by immersing them in an aqueous solution of dye, called dye liquor. Normally the dye liquor consists of dye, water and an auxiliary. To improve the effectiveness of dyeing, heat is usually applied to the dye liquor. The theory of aqueous dyeing, as explained below, is modified when an organic solvent is substituted for water. The general theory of dyeing explains the interaction between dyes, fiber, water and dye auxiliary. More specifically, it explains:
Forces of repulsion which are developed between the dye molecules and water. Forces of attraction which are development between the dye molecules and fibers.
These forces are responsible for the dye molecules leaving the aqueous dye liquor and entering and attaching themselves to the polymers of the fiber.
Dye molecules are organic molecules which can be classified according to the causing part of the color are listed bellow:
i) Anionic: In which the color is caused by the anionic part of the dye molecule.
ii) Cationic: In which the color is caused by the cationic part of the dye molecule.
iii) Disperse: In which the color is caused by the whole molecule.