Vat Dye

Vat Dye

Vat dyes are an ancient class of dyes, based on the natural dye, indigo, which is now produced synthetically. Vat dyeing is a process that refers to dyeing that takes place in a bucket or vat. Almost any dye, including fiber-reactive dyes, direct dyes, and acid dyes, can be used in a vat dye. Cotton, wool, and other fibers can be all dyed with vat dyes. Although almost all dyeing can be done in a vat, the term vat dye is used to describe a chemical class of dyes that are applied to cellulosic fibre (ie cotton) using a redox reaction as described below. Because of the use of caustic soda, and the very high ph of the dye bath in the dyeing process, wool cannot be dyed using vat dyestuffs. Wool is soluble in caustic soda solutions.