Determination of Bast Fiber Fineness via Standardized Low-Pressure Air Permeability
Low-pressure air permeability tests determine bast fiber fineness by measuring specific surface area across standardized compressed fiber plugs under ISO 2370.
Retting Degree Impact
Process Metric
Fibre preparation standards in linen manufacturing categorize the degree of enzymatic stem breakdown to predict carding efficiency and wet spinning performance. Evaluating retting degree impact allows mill technicians to assess how dew or warm-water retting duration alters fibre bundle division and ultimate yarn hairiness. Scutching facilities record retting severity scores on raw fibre consignment sheets to route flax batches toward appropriate yarn count production lines.
This quality metric applies to raw fibre bundles prior to hackling and does not measure fabric finishing characteristics.
Spinning Performance
Under-retted flax stems retain excessive calcium pectates that bind cortical bundles together, causing harsh fibre feel and high end-breakage rates during dry spinning operations. Conversely, over-retting allows fungal bacteria to attack secondary cell walls, destroying cellulose structural integrity and producing weak, dusty fibres that fail mill tensile specifications. By measuring retting degree impact, mill managers select specific blending ratios of coarse and fine scutched flax to achieve target yarn lea values and breaking tenacity.
Test laboratories perform fineness and bundle strength tests according to ISO 2370 to verify that retting levels conform to contractual grade definitions. Mill processing sheets link retting scores directly to drafting frame speeds and flyer spindle settings.
Value Constraint
Extreme over-retting causes irreversible fibre degradation that cannot be remedied through chemical softeners or modified drafting tension in spinning. Severely damaged fibre lots are downgraded to industrial non-woven or paper production streams.