Effect of Spinline Quenching on Structure Development in High-speed Melt Spinning of PET

<jats:title>Abstract</jats:title> <jats:p>In the high speed melt spinning of polyfethylene terephthalate), the spinline was quenched with a water-bath and diameter profiles were measured. The filament diameter measured just above the water-surface was much thicker than that of the asspun filament and the deformation of filament after it was immersed in the water was suggested. At a take-up velocity of 6000 m/min without a water-bath, neck-like deformation was observed. When the water-bath was set farther from the spinneret than the position of neck-like deformation, the diameter at the water-surface was still thicker than that of as-spun filament. In other words, neck-like deformations disappeared. The friction stress applied to running filament by the water was estimated from the measurement of spinline tension. The calculation of the temperature distribution in the filament cross-section revealed that cooling behavior in the water is governed not by heat transfer from a filament surface to the water but by heat conduction in the polymer. Rapid increase of spinline tension due to high friction stress by the water and relatively slow cooling of filament due to low heat conductivity of the polymer lead to the deformation of filaments in the water and disappearance of neck-like deformation.</jats:p>