Sulphur Dyes Today and Tomorrow

Sulphur dyes are the preferred dyes for dyeing corduroy, work wear and polyester-cellulosic fibre blend fabrics. The most important process variables are described briefly. Effluent problems arise when using sulphides as reducing agents and when oxidizing with dichromate. Instead of sulphide it is possible to use sodium hydrosulphite (sodium dithionite), mercaptoethanol, or glucose. On the other hand, sulphides can be eliminated very easily from the effluent by aeration or precipitation. Dichromate can be replaced by several products. The continuous determination of hydrogen peroxide, and the possibility of combining oxidizing and alkylation treatments are considered