Sizing Agent Selection for Fine Spun Bast Yarns
Optimal fine bast yarn sizing requires balancing PVA and CMC polymers to achieve eleven percent dry add-on without causing warp brittleness.
Shedding Friction
Mechanical Wear Force
Abrasive forces generated during the opening and closing of the warp yarn shed on the loom can cause surface damage to yarns. Excessive shedding friction occurs when the warp yarns rub against each other or against the healds and reed during loom operation. This physical contact can strip away the protective sizing layer and expose the raw fibres.
Yarn Degradation
Reciprocating movements of the loom harness rub the warp yarns continuously, causing hairiness to increase and fibres to fray. Managing shedding friction is particularly challenging with linen yarns due to the rigid nature of flax fibres. When the protective sizing film fails under this abrasive action, the protruding fibres can cling to adjacent yarns, preventing a clean shed opening and leading to loom stoppages.
This wear is mitigated by applying high-performance lubricants and sizing copolymers that reduce the coefficient of friction. Spun yarns must be regularly inspected for surface damage to ensure the sizing recipe is working correctly.
Weaving Efficiency
Reduced abrasion in the warp shed translates directly into fewer machine stops and higher fabric quality. Minimizing shedding friction preserves the tensile strength of the flax yarns throughout the entire cycle. This enables high-speed loom operation and increases the yield of first-quality fabric.