Fibre Composition
Raw bast fibre bundles contain structural components other than pure alpha-cellulose that influence spinning performance and bleaching requirements. Laboratory analysis of raw flax stock isolates non cellulosic impurities including pectins, lignins, waxes and water-soluble ash content. Pectic substances bind individual elementary fibres into technical bundles suitable for mechanical carding.
Mill entry quality certificates record total non-cellulosic mass percentage to determine appropriate retting efficiency and chemical consumption during subsequent boiling off operations.
Chemical Removal
Chemical preparation transforms raw grey flax yarn into purified bleached substrates through controlled degradation of non-polymeric binder networks. Sodium hydroxide boiling breaks insoluble protopectin into soluble sodium pectate, releasing individual ultimate fibres from the technical bundle matrix. Lignin fractions require oxidative treatment with sodium hypochlorite or hydrogen peroxide to avoid fiber tendering while achieving target whiteness levels.
Laboratory testing logs document weight loss percentages during scouring, where weight drops of twelve to twenty percent reflect the removal of non-cellulose compounds. Inadequate removal leaves stiff hydrophobic residues that impair dye penetration, whereas over-scouring weakens cellulose chain polymers and reduces yarn tensile strength.
Quality Grading
Finishing plants evaluate grey yarn samples before bulk processing to adjust chemical bath dosages. Residual levels of non cellulosic impurities dictate the final hand feel and absorbency of woven linen fabrics.
