Sulphur dyes are a type of dye made by sulfuration of aromatic amine or phenolic compounds using sulphur or sodium polysulfide as raw materials. Due to the presence of sulphur bonds (single sulphur bonds, double sulphur bonds, or poly sulphur bonds) in their molecules, they are called sulphur dyes.

Sulphur dyes are characterized by their low cost, simple dyeing process, easy color matching, and relatively good color fastness. However, their applications are limited due to uneven chromatography, lack of brightness, and poor dye fastness of some sulphur dyes.

Despite these limitations, sulphur dyes are suitable for dyeing cotton products with deep shades due to their low cost and good color fastness. These cotton products can be raw cotton, yarn, or fabric. For dyeing raw cotton and yarn, tub dyeing or package dyeing machines are commonly used, where the dye liquor flows and is forced through the fibers for dyeing. For dyeing fabric, there are various methods, including jig dyeing, pad dyeing, and dip dyeing. The specific method chosen based on product structure and batch size.

Application of Sulphur dyes:

Note：

①A--Na2CO3( g/L); B--x%(o.w.f.); C--Na2S:dyes=2~1:1; D--Na2SO4(5-10g/L) ;

②The dyes is applied in advance to the commendation(wetting);

③After add dyes,usually heat at 1℃/min,heating to 98-100℃,and then keep the temperature 45-60 min for dyeing.

④After dyeing,washing→Oxidation of air or oxidants,40℃ and keeping 20min→washing→drying