Extruded Band
Continuous untwisted ropes comprising thousands of solvent-spun cellulosic filaments form the primary intermediate delivery mass between wet-spinning spinnerets and staple fibre cutting operations. Produced during direct dissolution processing, lyocell tow consists of aligned, highly oriented regenerated cellulose filaments bundled together for continuous downstream bleaching, washing, crimping and finishing. The tow designation ends once mechanical rotary blades cut the continuous strands into discrete staple lengths or crimped nonwoven feedstocks.
Direct Dissolution
Chemical preparation involves dissolving dissolving wood pulp directly in aqueous N-methylmorpholine N-oxide monohydrate without forming intermediate chemical xanthate esters. The resulting viscous dope passes through spinneret plates containing tens of thousands of holes, entering a dry air gap before entering an aqueous spinning bath. Air gap drawing introduces high molecular orientation along the filament axis.
Precipitated filaments converge into a unified lyocell tow band, which passes through multi-stage counter-current washing units to remove and recover over ninety-nine percent of the amine oxide solvent.
Fibrillation Propensity
High longitudinal polymer alignment and a lack of transverse crosslinks create a structural tendency for surface microfibrils to peel away from the filament core when wet. Under mechanical friction in wet textile processing, lyocell tow derivatives split longitudinally, generating micro-fibrils on the yarn surface. Mills manage this characteristic intentionally, utilizing controlled enzyme treatments with cellulases to produce soft peach-skin surface finishes, or purchasing crosslinked lyocell variants where chemical crosslinkers prevent fibril detachment.
Cutter Delivery
Mechanical crimpers apply uniform waviness to the running tow bundle prior to staple cutting. Mill quality checkpoints inspect tow linear density, filament cross-sectional roundness and finish oil pick-up percentage to guarantee clean cutting performance and smooth carding through subsequent spinning preparatory machinery.
