Determining True Dry Fiber Mass through Laboratory Solvent Extraction Procedures
True dry fiber mass requires quantitative solvent extraction of non-fibrous processing aids prior to forced-draft oven drying to constant weight.
Yarn Finishing Oils
Chemical Composition
Chemical surface formulations suppress boundary friction and dissipate electrostatic charges to protect synthetic fiber filaments from thermal degradation during high-speed texturing operations. Applying yarn finishing oils ensures smooth filament movement over metal and ceramic machine guides during continuous draw-texturing operations. Formulations combine mineral oils or synthetic ester bases with emulsifiers, antistatic agents, oxidation inhibitors, and corrosion control additives.
Neat oil formulations apply directly without water carriers, while aqueous spin finishes use emulsified oil droplets suspended in water matrices.
Interfacial Friction
Running yarns generate significant friction when passing over friction disks, ceramic guides, feed rollers, and traveler rings at velocities exceeding one thousand meters per minute. Applied fluid films establish hydrodynamic lubrication layers that prevent direct fiber-to-guide contact and reduce filament abrasion. Lower friction values prevent individual filament breakage, eliminating loose filament loops that cause slubs and tension spikes during high-speed knitting.
Antistatic components dissipate triboelectric charges generated during rapid movement, preventing filament ballooning and web split failures.
Process Boundary
Liquid applications occur during synthetic filament extrusion, draw-texturing, filament drawing, or yarn coning, prior to fabric formation processes. Specifications exclude permanent fabric softeners and water-repellent fluorochemical coatings.
Scouring Removal
Downstream dye houses must scour out applied lubricant formulations using aqueous alkaline wash baths before high-temperature dyeing. Residual oil traces cause uneven dye uptake and smoke inside heat-setting stenters, requiring emulsifier systems that wash off completely at low scouring temperatures.