An approach to the dyeing of polyester fiber using indigo and its extended wash fastness properties

Polyester fiber was dyed with indigo vat dye to examine the practical dyeing feasibilities and behaviors. Vat dyes, which commonly applied to the cellulosic fibers, could be considerable colorants to dye polyester substrate, especially focusing on fastness aspect in terms of washing test. In this work, the optimized dyeing conditions and behaviors were investigated. In addition, extended multiple washings of indigo dyeing, which were compared with the results of disperse dyeing, were carried out to determine the fastness properties. HPLC analysis showed that when dyeing time increased, structural changes of indigo components were attributed to the decreasing color strength of dyeings. From the comparison of indigo disperse system and leuco system, it was found that disperse system of indigo had little effect to achieve dye uptakes.