Properties and Mechanism of Acid Dyes
by : Rahul Sharma
Properties Of Acid Dyes:
- These dyes are anionic in nature.
- These dyes are suitable for wool, silk, polyamide and modified acryllics.
- These are applied from a strongly acidic to netural pH bath.
- These dyes have no affinity for cotton cellulose's, hence not suitable for cellulosics.
- These dyes combine with the fiber by hydrogen bonds, vander waals forces or through ionic linkages.
Mechanism of dyeing with acid dyes:
The protein and polyamide fibers produce cationic sites in water under acidic conditions, as the acidity of the solution is increased more cationic sites are produced under these strongly acidic conditions. These cationic sites are thus available for the acid dye anions to combine with through hydrogen bonding, vander waals forces or ionic bonding. These linkages are strong enough to break , and thus dyeing produced are fast .
