Moisture Regain Adjustment Mechanics in Cross Border Scutched Flax Landed Contracts
Landed flax contracts adjust invoice mass by converting quay scale weights to dry cell wall mass using ISO 6741 oven tests before applying 12% standard regain.
Hysteresis Curve
Sorption Equilibrium
Graphic representations of moisture equilibrium in natural fibers illustrate the discrepancy between water absorption and desorption paths. The hysteresis curve for flax fibers plots the equilibrium moisture content against relative humidity, showing that a fiber holds more water during drying than during wetting. This difference occurs because the hydroxyl groups in the cellulose structure are already bound to water during the desorption phase, which prevents the immediate release of moisture.
This physical behavior dictates how flax reacts to ambient environment variations.
Fiber Processing
Industrial humidification systems in spinning mills utilize these curve values to maintain fiber pliability during drafting. During the wet spinning process, the flax passes through hot water to soften the pectin and activate the hysteresis curve transition to a high moisture state. This softening allows the fibers to slip smoothly past one another, yielding a fine and uniform linen yarn.
Yarn Testing
Commercial transactions for linen yarn depend on moisture calculations drawn from these curves. When testing yarn weight for shipment, the fiber must be conditioned to a standard moisture level along the absorption path to ensure consistency. This protocol prevents disputable measurements between the mill’s laboratory and the buyer’s quality control department.