Direct, or substantive, dyes are applied to the fabric from a hot aqueous solution of the dye. Under these conditions, the dye is more soluble and the wettability of natural fibers is increased, improving the transport of dye molecules into the fabric. In many cases, the fabric is pretreated with metallic salts or mordants to improve the fastness and to vary the colour produced by a given dye,
Properties and Applications:
Direct dyes are mainely used for to dye cellulose materials, such as cotton. this dyes is windely used in paper industry.
It is also be used for proteins fibre such as, silk and wool matrials.
It is used for dyeing of paper Or paper related materials. it is also used for dyeing of leather materials.