Sulphur Blue 7

Preparation

4-(4-Amino-3-methylphenylamino)phenol with Sodium polysulfide solution in return 106 ~ 112 ℃ heating 50 hours, then 70 ~ 80 ℃ blow air make precipitation. This indophenol?is by o-Toluidine and 4-Nitrosophenol in sulfuric acid, and then the condensation with Sodium polysulfide and reduction. Sodium polysulfide increase in the proportion of sulfur content and high temperature vulcanization, color is red and more bright-coloured dye.

Properties and Applications

red light blue to blue light purple. Royal purple powder. Insoluble in water. In the Sodium sulfide solution solubility is good, for green grey; In concentrated sulfuric acid for blue purple, dilution of dark after precipitation. Dyeing content in alkaline insurance powder for the pale yellow light olive, oxidation, to restore the original colour and lustre. In sodium hypochlorite solution all faded. Mainly used for cotton, hemp, viscose fiber and vinylon/cotton blended fabric dyeing. Also used in cotton direct printing and leather, paper dyeing.