2-Naphthalenesulfonic acid, 8,8'-[carbonylbis[imino(2-sulfo-4,1-phenylene)azo]]bis[7-(methylamino)-, tetrasodium salt

1,3-Bis(4-amino-3-sulfophenyl)urea double nitriding, and 7-Aminonaphthalene-2-sulfonic acid?(2 Moore) coupled.

blue light pink. Soluble in water for red, slightly soluble in ethanol is palm red light product. The strong sulfuric acid for orange red brown, diluted purple for grey brown. The dye solution to join strong hydrochloric acid for brown, have precipitation; Add thick sodium hydroxide solution for product red

Standard	Acid Resistance	Alkali Resistance	Light Fastness	Soaping		Water
				Fading	Stain	Fading	Stain
ISO	3	5	3	1		1