Properties of dyed wool fabrics in terms of hygral expansion and permanent setting

The hygral expansion of wool fabric was determined before and after each of a variety of blank-dyeing and dyeing processes. Acid milling was applied, and dyes such as metal-complex, chrome and reactive ones were used. The permanent set level, the fibre mechanical properties, its thermal stability and characteristic temperatures were determined. The main objective was to study the effect of dye-fibre interactions and the influence of dyeing recipes on fabric hygral expansion and permanent set. It was found that wool fabric's physical and mechanical properties, as well as the hygral expansion change during piece-dyeing, underwent changes which were caused mainly by the dyeing conditions. However the dye-fibre interaction influences the fibre damage and the level of set, and consequently affects the fabrics' hygral expansion. The influence of dichromate used in the afterchrome dyeing on fabric hygral expansion was also established.