Reuse of wastewaters on dyeing of polyester fabric with encapsulated disperse dye

The textile industry can benefit from the use of microcapsules, both adding value to products through the production of technical or functional textiles and improving the processes in the production chain. Some applications have been widely explored in academic research, but many are not feasible for use in industrial scale. Thus, the aim of this study was to develop consistent and efficient methodologies for the encapsulation of active compounds commonly used in the textile industry, employing materials which are viable for large-scale application. In this study, polyurethane-urea microcapsules were formulated by interfacial polymerization and encapsulated with C.I Disperse Blue 60 for the dyeing of polyester fabric without the use of dispersing agents and other auxiliaries. The dyeing was carried out in a high temperature dyeing machine with a very simple dyebath, in which there are only dissolved dye molecules, microencapsulated dyes and the fabric. Additionally, the dyebath wastewaters were reused on a further dyeing as 100% bathwater and mixed with 50% distilled water. Colorimetric measurements show excellent colour removal in both samples.