2,7-Naphthalenedisulfonic acid, 5-amino-4-hydroxy-3-[[4-[(4-sulfophenyl)azo]-1-naphthalenyl]azo]-, trisodium salt

4-Aminobenzenesulfonic acid diazo, and Naphthalen-1-amine coupling, its product to diazo, in alkaline conditions and 4-Amino-5-hydroxynaphthalene-2,7-disulfonic acid?coupling.

blue and black. Soluble in water for a blue-black, easily soluble in soluble fiber element, insoluble in other organic solvents. In the dark for the strong sulfuric acid, after diluted blue-black precipitation; In the dark for strong nitric acid solution, and then into a chestnut; In 10% of sodium hydroxide solution for black solution in red.

Standard	Light Fastness	Soaping		Persperation Fastness	Oxygen bleaching		Fastness to seawater
		Fading	Stain		Fading	Stain	Fading	Stain
ISO	6-7	4	3-4	3	4	4	4	3-4
AATCC	7-8	4	4	1	2	2	3	3