Determining Dry Mass Regain in Flax Roving Processing
Determining dry mass regain in flax roving requires 105°C thermal drying coupled with solvent extraction corrections to separate water loss from spinning oils.
Boiled Flax Regain
Standard Fraction
Fiber moisture standards establish the permissible water ratio retained by processed flax after boiling treatments during yarn preparation. In linen yarn manufacturing, boiled flax regain refers to the standardized percentage of moisture that flax fiber must contain after boiling to remove natural impurities. Mill laboratories calculate this percentage against the oven-dry weight of the scoured material.
This is recorded on the moisture test sheet.
Boiling Impact
Removal of natural pectins and waxes during the boiling process alters the hydrophilic behavior of the flax fiber. When raw flax undergoes alkaline boiling, the loss of non-cellulosic components reduces the total sites available for water molecule binding. Consequently, the fiber displays a lower moisture capacity compared to raw flax.
This physical change necessitates a specific yarn-grade standard to prevent over-valuation of the shipped material. Spun yarn undergoes these evaluations to ensure that the chemical alterations from scouring are fully accounted for before the spinning oil application stage.
Commercial Weight
Adjusting the invoicing weight based on standard regain values prevents financial losses during bulk transactions. If the actual moisture measured at the export gate exceeds the agreed boiled flax regain, the commercial invoice weight is adjusted downward. Mill managers enter these results directly into the shipment dispatch log.
This maintains transaction accuracy.