Thermal Loss
Chemical degradation during the alkaline removal of non-cellulosic impurities defines scouring weight loss within the finishing stages of a linen mill. Boiling flax roving in sodium hydroxide removes residual pectins, hemicellulose and wax compounds adhering to the elementary fibres. Extracted non-cellulosic matter dissolves into the liquor, reducing the total dry mass of the processed yarn.
Mill technicians record this percentage change on the technical batch sheet before the material moves to bleaching tanks. The calculation subtracts post-scour bone-dry mass from pre-scour bone-dry mass, dividing the difference by the initial mass. This analytical step stops applying once the alkaline bath drains and rinsing water achieves neutral pH levels.
Fiber Reduction
Chemical removal alters the physical structure of flax yarn by stripping binding gums from cellulose microfibrils. Plant extractives account for a specific fraction of raw line flax, and caustic boiling dissolves those components completely. Excessive alkali concentration accelerates cellulose depolymerization, forcing the mass reduction beyond target parameters.
Laboratory analysts measure the dissolved organic carbon in spent liquor to verify whether the loss stems from natural gums or damaged cellulose chains. Excessive mass reduction weakens tensile strength, leaving finished linen vulnerable to breakage during high-speed shuttle weaving.
Acceptance Criteria
Commercial purchase contracts specify exact tolerance ranges for mass reduction during chemical processing to protect fabric integrity. Mills maintain internal limits that vary according to flax variety and yarn count, ensuring the material retains sufficient weight for subsequent dyeing operations. Buyers verify these factory records against independent laboratory tests before signing bills of lading for exported cloth.
Excessive reduction invalidates warranty claims regarding finished fabric durability, transferring financial liability back to the spinning facility. Precise control over chemical parameters prevents substandard batches from reaching international markets.
