Effect of metallic wire inserted in nozzle in high-speed melt spinning of poly(ethylene terephthalate)

✍ Scribed by Hyung Joong Jeon; Hiroshi Ito; Takeshi Kikutani; Norimasa Okui; Miyoshi Okamoto

• Publisher: John Wiley and Sons
• Year: 1998
• Tongue: English
• Weight: 270 KB
• Volume: 70
• Category: Article
• ISSN: 0021-8995
• DOI: 10.1002/(sici)1097-4628(19981024)70:4<665::aid-app5>3.0.co;2-o

✦ Synopsis

High-speed melt spinning of poly(ethylene terephthalate) was performed using a spinning nozzle with an inserted metallic wire of various lengths (0, 8, 30, and 45 mm). The molecular orientation of as-spun fibers increased with the increase in the wire length at all the take-up velocities examined. Along with the enhanced molecular orientation, the longer wire length led to the starting of orientation-induced crystallization at lower take-up velocities. The structure of crystallized fibers obtained at low speeds can be characterized by high crystallinity and relatively low molecular orientation. From the on-line measurement of the diameter and temperature profiles of the spin line with the 30-mm metallic wire, it was revealed that the spin-line had a maximum diameter of about 6 mm at the wire end. The spin-line temperature at this position was about 190°C. The solidification of the spin-line occurred at positions much closer to the spinneret in comparison with ordinary high-speed spinning. These results show that high-speed spinning with a wire inserted in the nozzle corresponds to a spinning process operated at extremely low extrusion temperature using a nozzle with an extremely large diameter. From the starting of orientation-induced crystallization at lower levels of birefringence in comparison with ordinary high-speed spinning, the alteration of the inherent fiber structure that cannot be represented by birefringence was also suggested.