Sizing Chemistry

Solution Viscosity

Rheological behavior determines the penetration depth of sizing chemistry into the interior structure of natural flax yarns. High shear rates inside the application trough temporarily lower fluid resistance, allowing the liquid to coat internal capillaries before drying on heated cylinders. Mills verify fluid thickness through rotational cup tests and record the resulting centipoise values on the technical specification sheet.

Excess thickness leaves surface crusts that flake off into airborne dust, while thin solutions fail to protect individual fibers against heald wire friction.

Residue Level

Gravimetric extraction measures the dry weight percentage of sizing chemistry retained on the woven fabric surface prior to alkaline scouring. Laboratory technicians boil small cloth samples in enzymatic baths to strip away the starch layer completely. The resulting mass differential establishes whether the grey cloth meets export merchant acceptance criteria or requires secondary enzymatic desizing.

Fabric grade assessments depend entirely upon complete removal because residual starches interfere with subsequent dye uptake and chemical bleaching stages.