Optimizing Sizing Formulations to Prevent Tensile Decay in Flax Warp Yarns
Optimizing flax warp size with modified starches and acrylic binders locks inner fiber bundles, preventing tensile decay and cutting loom stop costs.
Dry Add-on Calculation
Mathematical Formula
Gravimetric mass ratios express the exact proportion of dry sizing solid deposited onto raw yarn relative to unsized yarn bone-dry weight. Linen warp preparation relies on dry add-on calculation to establish sizing uniformity across multiple beam sets. In Chinese weaving mills, this dry add-on calculation determines the real chemical uptake by accounting for natural moisture regain alongside sizing solution refractometer Brix values.
The computation excludes volatile water evaporated across drying cylinders, isolating the true mass gain of dry starches and polymers on the yarn substrate.
Operational Variable
Processing parameters during slashing dictate actual solid deposition across flax bundle crevices. Size box concentration, machine velocity, squeeze roller durometer hardness and nip pressure alter the wet pick-up quotient. Squeeze roller pressures typically range around twenty kilonewtons in commercial linen sizing ranges.
Variations in yarn moisture regain, which fluctuates substantially in bast fibres according to ambient humidity, skew gravimetric results if raw yarn dry tare is not established beforehand. A dry add-on calculation operates on oven-dried sample pairs taken before the size trough and immediately after cooling section passage. Mill technicians log wet pick-up percentages alongside drying cylinder temperatures to prevent over-drying, which embrittles flax cellulose and induces shedding.
Verification Standard
Weaving acceptance criteria require specific dry solid percentages tailored to yarn linear density and loom speed. Coarse flax warps frequently target seven to ten percent dry add-on, whereas high-count yarns need lower loadings between five and seven percent. Mill quality documentation records dry add-on calculation results on sizing shift logs that accompany warp beams to the loom house.