Polymer Coating Volume
Protective coatings applied to warp yarns provide the abrasion resistance needed for high speed weaving. Polyvinyl alcohol sizing add-on refers to the dry weight of the polymer deposited on the yarn surface, expressed as a percentage of the original yarn weight. This chemical, often abbreviated as PVA, is preferred for linen because it forms a tough and flexible film that prevents the brittle flax fibers from shedding or fraying.
The correct amount of sizing ensures that the yarn remains intact through the reed and healds during industrial operation.
Weaving Efficiency Correlation
Proper calibration of the size box and the concentration of the sizing liquor determines the final amount of polymer on the yarn. If the polyvinyl alcohol sizing add-on is too low, the yarn will lack the protection needed to survive the friction of the weaving process, leading to frequent breakages. Excessive amounts of the polymer make the yarn overly stiff, potentially causing failures due to brittleness or complications during the subsequent desizing stage.
Chinese mills monitor the pickup rate by weighing samples of the yarn before and after the sizing process. This data helps in maintaining a consistent quality across different production runs.
Desizing Wash Requirement
Removal of the size before dyeing is essential for ensuring even color absorption. High levels of PVA require more intensive washing cycles and higher water temperatures to completely clear the fiber surface. Clean fibers dye better.
