Polymer Coating
Synthetic polyvinyl alcohol sizing formulations applied to spun linen warp yarns provide protective surface films and abrasion resistance during high-speed weaving operations. Bast fibre yarns possess surface hairiness and lower elasticity compared to synthetic yarns, requiring chemical binding to withstand reed friction. Utilizing PVA warp size increases yarn tensile strength and reduces fiber shed on shuttleless looms.
Desizing processes must remove the film completely during fabric finishing to ensure uniform dyeing and bleaching.
Application Process
Concentrated PVA sizing solutions are prepared in heated mixing kettles at eighty-five degrees Celsius before delivery to slasher size boxes. Warp yarns pass through size liquor immersion rollers and rubber squeeze rolls to apply controlled chemical pickup percentages. Slasher drying cylinders evaporate moisture, forming a flexible, transparent protective film surrounding individual yarn shafts.
Formulations incorporating PVA warp size often include film softeners and lubricants to reduce yarn brittleness without compromising tensile adhesion. Quality technicians monitor liquor concentration using refractometers and test size add-on percentages via dry mass weighings. Correct viscosity control ensures uniform liquor penetration into spun linen yarn structures without creating stiff yarn bridging.
Slasher operators record yarn speed, squeeze roller pressure and drying cylinder temperatures on batch processing sheets for every warp beam.
Weaving Performance
Coated warp yarns demonstrate reduced break rates under high mechanical tension on rapier and air-jet looms. Film protection minimizes fiber shedding and lint accumulation inside loom harness eyes and drop wires. Efficient desizing in hot water baths removes residual size before bleaching or dyeing operations begin.
Proper sizing formulation directly improves loom efficiency percentages and gray cloth visual appearance.
