High-Temperature Zone-Drawing for Nylon 6 Fibers

• Published in: KOBUNSHI RONBUNSHU 1992/02/25, Vol.49(2), pp.161-167
• Main Authors: KUNUGI, Toshio, SUZUKI, Akihiro, KUBOTA, Emi
• Format: Article
• Language: Japanese
• Subjects: Applied Tension; Drawing Temperature; High Modulus Fiber; High-Temperature Zone-Drawing; Nylon 6 Fiber
• ISSN: 0386-2186; 1881-5685
• DOI: 10.1295/koron.49.161

In order to improve the mechanical properties of nylon 6 fibers, the high-temperature zone-drawing (HT-ZD) was applied. This HT-ZD method is intended to help unfold lamellae and stretch molecular chains. In the present study, the HT-ZD method was carried out over the drawing temperature range from 190°C to 215°C, close to the melting point of 220°C. The draw ratio, birefringence, crystallinity, amorphous orientation factor and Young's modulus for the HT-ZD fibers increased with increasing the drawing temperature up to 210°C. The HT-ZD fiber zone-drawn at 210°C has a draw ratio of 5.3, birefringence of 56.3×10-3, crystallinity of 51%, amorphous orientation factor of 0.57 and Young's modulus value of 5.9 GPa. However, the bireringence, amorphous orientation factor and Young's modulus of the fibers zone-drawn above 210°C decreased drastically with increasing the drawing temperature. The HT-ZD fiber zone-drawn at 215°C has a birefringence of 7×10-3, a crystallinity of 38%, an amorphous orientation factor of about zero and Young's modulus value of 0.9 GPa. These values are the same as the values of the original fiber. Consequently, the most suitable conditions of first HT-ZD were found to be a drawing temperature of 210°C and an applied tension of 2 kg/mm2. To improve the mechanical properties further, the HT-ZD was repeated 3 times at the constant drawing temperature of 210°C, by increasing the applied tension. The mechanical properties were improved with such processing: the fiber zone-drawn 3 times has a Young's modulus of 7.4 GPa and a dynamic modulus of 12 GPa.