Yarn Count and Sizing Chemistry in Warp Preparation
Warp sizing requires matching yarn packing factor to polymer viscosity, adjusting squeeze nip pressure for precise solids add-on, and maintaining elongation.
Tensile Tenacity Gain
Strength Increase
Proportional increase in the breaking strength of yarn achieved by the application of sizing polymers prepares the warp for loom stresses. Laboratories calculate the tensile tenacity gain to evaluate the effectiveness of the starch or polyvinyl alcohol size formulation. This improvement is measured by comparing the force required to break a sized yarn against that of an unsized yarn.
Its level must be sufficient to survive the rapid shedding motions of high-speed looms.
Sizing Contribution
Linen warp yarns are subjected to high tension and abrasion from the loom’s reed and healds. To protect these fibres, the sizing paste penetrates the yarn structure and coats its outer surface, thereby increasing the yarn’s resistance to tensile forces. This tensile tenacity gain is influenced by the concentration of the size mix and the pressure applied by the squeeze rollers.
Too little polymer application yields insufficient strength, while excessive application makes the yarn stiff and brittle. Spinners must fine-tune this chemical pick-up to achieve the optimal balance between flexibility and tensile strength.
Quality Threshold
Quality control teams conduct daily single-yarn strength tests to record this parameter. The results are logged in the batch certificate. High strength gains correspond directly to lower warp break frequencies in the loom room.