Sulphur Black 6

4-(Naphthaleti-2-ylamino)phenol and a small amount of 4-Nitrophenol and 4-Methylbenzene-1,3-diamine with Sodium polysulfide tert – Butanol solution at 110 ~ 112 ℃ reflux heating 30 hours, and finally as C.I. Sulphur Black 11 (C.I. 53290) – sample, with Sodium nitrite oxidation (BIOS 983130-138). The dye than most sulfur dye has good resistance to chlorine bleaching fastness.