Thermal Preparation
Alkali immersion precedes mechanical extraction within the wet processing workshops of Jiangnan flax mills during preliminary stem conditioning. Alkaline scouring liquor dissolves pectin bonds that bind bast fibres inside raw stems before roving boiling pretreatment occurs in pressurized vertical kiers. Hot caustic sodium solutions operate at high temperatures under controlled pressure to strip remaining non-cellulosic gums from unspun plant matter.
Mill technicians record these chemical parameters on production logs alongside fiber yield percentages prior to spinning frame allocation.
Fiber Assessment
Laboratory personnel evaluate treated strands against export-grade specifications outlined in enterprise quality manuals before yarn formation begins. Tensile strength measurements establish whether processed bast stocks meet baseline requirements for fine linen fabric production. Mill managers establish acceptance thresholds independently from foreign buyer demands to maintain internal process control across spinning lines.
Strict laboratory protocols separate raw fiber classifications from woven textile standards by measuring elongation properties directly on conditioned samples.
Export Classification
Final inspection documents accompany finished yarn lots through customs clearance channels toward international garment manufacturers. Commercial grade assignments reflect residual lignin content and fiber fineness values determined during earlier wet stage testing. Export documentation formally verifies chemical bath compliance without disclosing proprietary mill formulations to external auditors.
Commercial agreements rely upon these standardized grade assignments rather than subjective visual appraisals to govern cross-border linen trade.
