Molecular Bridging of Lyocell Fibers with Multifunctional Cross-Linkers for Durable Antifibrillation Finishing

Lyocell fibers are prone to fibrillation under wet mechanical action, which limits their durability and further processing. In this study, three multifunctional cross-linkers with different molecular structures, including two aziridine-based cross-linkers (N1 and N3) and one isocyanate-based cross-linker (N2), were investigated for antifibrillation finishing of Lyocell fibers, yarns, and fabrics. The optimized conditions were 8% o.w.f. N1 at pH 9 and 60 °C, 6% o.w.f. N2 at pH 10 and 60 °C, and 6% o.w.f. N3 at pH 9 and 80 °C, with a treatment time of 4 h. Under these conditions, the dissolution time of cross-linked fibers in 70% ZnCl2 increased to approximately 70 min, approaching that of commercial A100. The whiteness values of N1-, N2-, and N3-treated Lyocell were 75.24, 74.08, and 72.72, respectively, while bursting strengths remained at 366.1–373.6 N. Cross-linking reduced water retention but maintained water absorption at approximately 6 g g–1. Reactive-dye exhaustion, fixation, color strength, levelness, and color fastness were also largely preserved. These results demonstrate that intermolecular cross-linking effectively suppresses Lyocell fibrillation while maintaining key physical and dyeing properties.