Dyeing of polyester using micro-encapsulated disperse dyes in the absence of auxiliaries

Polyurea microcapsules were prepared in this study, using disperse dye as the core material and diphenylmethane-4,4'-diisocyanate as the wall-former. Microencapsulated disperse dyes have been characterised in terms of their thermal properties, average particle size and size distribution, morphological structure and composition. Polyester fabric was dyed with microencapsulated CI Disperse Blue 56 using a high temperature dyeing process without dispersing agents, penetrating agents, levelling agents or other auxiliaries. The quality of the polyester fabric dyed in this manner – without reduction clearing – was at least as good as that dyed traditionally after washing and reduction clearing. After separating off the polyurea microcapsules, the dyebath was virtually colourless and was shown to be suitable for reuse.