CONCURRENT DIRECT DYEING AND EASY-CARE FINISHING OF VISCOSE AND WOOL VISCOSE BLEND FABRICS

An investigation is described in which conditions for simultaneous direct dyeing and resin-finishing of viscose and wool/viscose-blend (50/50) fabrics were established. Results obtained indicate that (a) the extent of the cross-linking reaction and dye interaction is determined by the kind of catalyst, the nature of the substrate, and the type of finishing agent; (b) the greater extent of dyeing and cross-linking observed in the presence than in the absence of the wool component is most probably due to the change in fibre structure as well as the incorporation of specific functional groups into the molecular structure of the wool component; (c) the enhancement of dye fixation in the presence of the finishing agent may be attributed to the fixability of the dye used to the substrate backbone through ionic salts, hydrogen bonding, van der Waals forces, physical entrapment by the resin, and/or chemically via the finishing-agent functional groups; and (d) for optimization, it is advantageous to carry out the combined process under the following conditions: the fabrics are padded in a bath containing Cassurit HML (50 g/L) and NH4Cl (7.5 g/L), together with the direct dye and in the presence of a non-ionic wetting agent (2g/L), to 80% wet pick-up, followed by the drying at 100-degrees-C/degrees-3 min and curing at 140-degrees-C/2 min; the dyeing are then washed thoroughly, soaped, and finally air-dried.