Chemical Structure
Natural polysaccharide compounds bind individual flax bast fibers into bundles within the plant stem. During the extraction of spinnable fiber, calcium pectate hydrogel acts as the primary adhesive agent that must be partially degraded to allow separation without causing strand breakage. This calcium pectate hydrogel consists of crosslinked polygalacturonic acid chains held together by divalent calcium ions.
These ionic bridges create a water-retaining matrix that maintains the structural integrity of the unrefined flax bundle.
Spinning Behaviour
High temperature water baths in wet spinning frames soften the pectin matrix to facilitate the sliding of fibers past each other. This softening of calcium pectate hydrogel reduces the cohesive force within the roving, which allows the drafting zone to draw the strand down to the target yarn count. If the water temperature remains too low, the calcium pectate hydrogel fails to transition into a sufficiently fluid state, resulting in thick places or frequent yarn breakages on the spinning line.
The drafting force must overcome the shear resistance of this gel to achieve uniform attenuation. Mill operators adjust the chemical hardness of the basin water because excessive sodium ions can displace the calcium, leading to premature dissolution of the adhesive matrix and roving degradation during the draft.
Extraction Boundary
Chemical scouring processes during yarn finishing target the remaining pectins to improve yarn softness and absorbency. When the calcium pectate hydrogel is completely stripped by overly aggressive alkaline boiling, the yarn loses its tensile strength and suffers from excessive hairiness. Spinning mills therefore monitor the residual pectin content to ensure the yarn retains enough binding matrix to withstand high speed weaving tension.
The treatment must be terminated before the core fiber bundles are destabilised.
