Reduction of Fibrillation of Lyocell Fabric in Continuous Dyeing
Lyocell is one of the recent regenerated cellulosic fibres. It is produced by an environmentally friendly process from wood pulp. Chemical structure of lyocell is similar to that of cotton and other regenerated fibres. The main difference is of the length of polymer chains (degree of polymerization).The main technical problem with this fiber is its ease of fibrillation. Fibrillation becomes apparent when fiber is abraded in wet state during pre-treatment and dyeing. The reason of such change of lyocell fibre surface is due to its physical structure (i.e. arrangement of polymer chains in amorphous and crystalline regions). Lyocell fabrics were processed by continuous dyeing method to observe the fibrillation effects. Cross-linking agents were applied before and after dyeing to see their effect on fibrillation. The fibrillation was assessed by observing the fiber morphology on Scanning Electron Microscope (SEM). The samples were also tested for color fastness to washing. Further, the color assessment k/s was performed to compare color yield of dyed, dyed cross-linked and cross-linked samples. The cross-linked dyed and dyed cross-linked samples were found to have reduced fibrillation. There was not any significant difference in colorfastness of dyed, dyed cross-linked and cross-linked dyed fabrics and the fastness was generally very good to excellent.