Spun-dyed lyocell

Cellulose pulp was dyed with a vat dye in an exhaust dyeing process. The dyed pulp, mixed with undyed pulp, was dissolved in NMMO and spun to obtain ‘spun-dyed’ lyocell fibers. The dyeing behavior of pulp and fastness properties of the spun-dyed fibers were compared with that of different cellulosic substrates dyed with the same vat dye. The cellulose pulp exhibited the highest degree of dye exhaustion as compared to lyocell fabrics (woven and knit), yarns, fibers, and woven cotton. The spun-dyed lyocell fibers exhibited superior light fastness as compared to conventionally dyed cotton and lyocell substrates. The spun-dyeing process is believed to involve lower costs than conventional dyeing and to be more eco-friendly. The fiber spinning process did not appear to be detrimental to the color in spun-dyed fibers.