Fibre Scouring
Natural wax removal in flax processing strips pectic compounds and intercellular lipids from the bast fibres before spinning takes place. Alkaline baths using sodium carbonate at elevated temperatures dissolve hydrophobic outer layers to prepare the cellulose for uniform moisture absorption during wet drafting. Jiangsu mills regulate surfactant concentration strictly within washing vans to prevent alkali burn on the cellulose polymer chains.
Residual soap fractions above four percent interfere with subsequent drawing frames by causing slivers to stick against brass rollers.
Scour Purity
Solvent extraction methods isolate wax fractions from random composite samples taken across imported flax bales to establish baseline grease levels prior to processing. Ether solubility tests measure residual lipid mass down to milligrams per kilogram of dry fibre weight. Export quality certificates record these baseline readings against mill acceptance thresholds agreed during contract negotiations between spinners and merchant houses.
Residual Saponification
Alkali carryover from preceding treatment stages neutralizes acidic sizing agents applied during subsequent warp preparation on high speed projectile looms. Laboratory titrations determine free hydroxyl alkalinity within rinse water discharges to maintain neutral pH levels across the finishing range. Fabric inspectors reject woven linen showing uneven dye uptake caused by localized surfactant retention in yarn cores.
