Yarn Protection Process
Applying an adhesive chemical formulation onto sheeted lengthwise yarns deposits a protective external film and bonds internal fibers together to withstand the mechanical stresses of high-speed weaving. Known across industrial textile manufacturing as warp sizing or slashing, this wet preparatory process treats thousands of parallel yarns simultaneously on continuous processing ranges before beam winding. Production planners schedule sizing runs for natural staple yarns and filament warps to prevent yarn rupture and fiber fraying during weaving cycles.
The mechanical and chemical scope encompasses size application, drying, splitting and beaming, ending where the sized warp beam mounts onto the loom let-off stand.
Mechanical Execution
Operational sizing machines draw warp sheets from multiple section beams through a chemical size box containing heated adhesive liquor. Squeeze rollers press wet size into yarn bundles under controlled pneumatic pressure to balance chemical pick-up against core penetration. The saturated warp yarn array travels immediately across steam-heated drying cylinders, evaporating moisture while preventing adjacent ends from gluing permanently together.
Leasing bars split the dried warp yarn sheet into individual ends, after which a headstock winds the yarn uniformly onto a single weaver beam under precise tension control.
Chemical Formulation
Sizing formulations combine polymeric film formers, lubricating softening agents, wetting auxiliaries and antistatic compounds tailored to specific fiber substrates. Cellulosic warps rely on modified starches, carboxymethyl cellulose or polyvinyl alcohol to build smooth adhesive coatings, while synthetic filament warps demand polyacrylic or polyester resin dispersions. Sizing agents increase single yarn tensile strength, raise yarn abrasion resistance and flatten loose surface hairs that would otherwise entangle adjacent yarns during shedding.
Lubricants like hydrogenated tallow or synthetic waxes reduce yarn-to-metal friction against drop wires, heald eyes and reed dents.
Process Control
Monitoring size add-on percentages ensures optimal performance, as insufficient pick-up leaves yarns vulnerable to loom abrasion while excessive add-on induces film brittleness and high size shed. Sizing efficiency displays direct correlation with loom stop frequencies, where properly sized beams achieve elevated weaving efficiency and minimal yarn breaks per hundred thousand picks. Moisture sensors track residual water content at the exit of drying sections, keeping moisture regain within fiber-specific tolerances to prevent yarn mold growth or yarn elongation loss.
Desizing evaluations verify that sized warps release applied polymers cleanly during subsequent wet finishing without interfering with dyeing consistency.
