The most commonly used dyestuffs in dyeing polyester fibers are disperse dyestuffs. Disperse dyestuffs have suitable fastness values and sufficient color palette on polyester fibers. It is commercially available in liquid or powder form.
Dissolution of disperse dyestuffs in water is not in the usual sense like the dissolution of other water-soluble dyestuffs.
Disperse dyestuff is suspended in the bath during the dyeing of polyester. That is, the dye molecules remain suspended in the bath without dissolving.