6420-43-5

4-Amino-3-methylbenzenesulfonic acid diazo, in acetic acid medium and N,N’-bis(4-hydroxy-2-sulfonaphthalene-7-yl)urea coupling, O-Methylaniline?diazo, in alkaline conditions and accidentally coupled nitrogen compounds.

colourful yellow red. Soluble in water for colourful red, insoluble in ethanol as a pale orange red, insoluble in other organic solvents. The strong sulfuric acid in red for quality, to orange diluted. The dye solution to join strong hydrochloric acid for orange brown, have precipitation; Add thick sodium hydroxide solution have red light orange brown precipitation.

Standard	Acid Resistance	Alkali Resistance	Light Fastness	Soaping		Water
				Fading	Stain	Fading	Stain
ISO	4-5	4	2-3	3		3
AATCC	5	4	3	3		3-4