Direct Black 56

Preparation

aniline diazo, and 5-Aminonaphthalene-2-sulfonic acid and 8-Aminonaphthalene-2-sulfonic acid coupling, again diazo, and 5-Aminonaphthalene-2-sulfonic acid and 8-Aminonaphthalene-2-sulfonic acid coupling, product to diazo, in alkaline conditions and 6-Amino-4-hydroxynaphthalene-2-sulfonic acid? coupling.

Properties and Applications

red light grey. Gray powder. Soluble in water for dark purple, not soluble in alcohol. The strong sulfuric acid in the green light for gray blue, diluted into purple. The dye solution to join strong hydrochloric acid have precipitation of dark; Add thick, hydrogen oxidation solution have dark purple precipitation. Cellulose fiber of dyeing, the dye well after sex is good, in the 80 ℃ temperature when the biggest affinity. Discharge sex is good, hard to sensitive. For the red light gray color. Dye in bath of copper, iron ion colored light basic unchanged, the SDC classification for a class B. Neutral and alkaline white are 5 levels. Mainly used for cotton, linen, silk, cellulose fiber fabrics such as glue the dyeing. Can also be used for leather, paper all the dyeing.