[1,1'-Biphenyl]-3,3'-dicarboxylicacid,4-[2-[1-hydroxy-6-(phenylamino)-3-sulfo-2-naphthalenyl]diazenyl]-4'-[2-(1-hydroxy-5-sulfo-2-naphthalenyl)diazenyl]-,sodium salt (1:4)

2-Amino-5-(4-amino-3-barboxyphenyl)benzoic acid?double nitriding, first and 5-Hydroxynaphthalene-1-sulfonic acid coupling, and then in alkaline conditions and 4-Hydroxy-7-(phenylamino)naphthalene-2-sulfonic acid coupling.

blue purple to red light blue. Soluble in water for purple, slightly soluble in alcohol. In the strong sulfuric acid as dark blue, purple for colourful after diluted. The dye solution with strong hydrochloric acid has the purple sediment: add thick sodium hydroxide solution for purplish red color.

Standard	Acid Resistance	Alkali Resistance	Light Fastness	Soaping		Water
				Fading	Stain	Fading	Stain
ISO	3-4	3-4	6	4		4-5