Calculating Raw Linen Greige Off-Loom Mass Loss
Off loom mass loss in linen greige averages 14 to 22 percent, requiring correction for sizing pickup, moisture regain, and non cellulosic scour extraction.
Warp Size Pickup
Size Retention
Starch and polyvinyl alcohol solution adherence forms the dry solid film left on flax yarns after passage through the sizing trough during preparation for weaving. Warp size pickup is calculated by measuring dry weight differences between untreated yarn and sized yarn expressed as a percentage of initial mass. Chinese mills operate sizing machinery at specific speeds to deposit protective coatings between eight and twelve percent of total dry weight.
Insufficient solids leave yarn abrasion points unprotected during high speed shedding action on multi phase looms. Excess coating creates stiff bundles that lack flexibility and snap under sudden tension loads during reed motion.
Mechanical Tension
Liquefor pressure adjustments regulate squeezing roller load inside the sizing box to control moisture retention and adhesive layer thickness simultaneously. Warp size pickup depends directly upon squeezing nip pressure, starch bath temperature, and immersion time during the wet passage phase. Heavier sizing formulations require greater mechanical force to strip surplus liquid from the yarn surface before drying cylinders evaporate residual water.
Insufficient nip pressure permits heavy liquid retention that causes adjacent ends to stick together during the subsequent drying phase. Modern sizing machines monitor wet pick up continuously to stabilize dry weight figures across entire production runs destined for export markets.
Export Specification
Technical sheets accompanying merchant linen rolls record the exact solid mass ratio to confirm compliance with buyer acceptance criteria agreed prior to spinning contracts. Warp size pickup determines subsequent desizing efficiency in downstream finishing plants where excess starch hinders uniform bleaching and dyeing reactions. Buyer standards typically allow a two percent tolerance band around the contractual target value to accommodate natural variations in raw flax fibre absorption capacity.
Laboratory testing of extracted yarn samples provides official documentation required for customs clearance and quality verification before international shipment proceeds.