Studies on High Speed Spinning of PET

Abstract

Abstract It is observed that preoriented yarn (POY) begins orientating crystallization near the area of sharp structural change through the measurements of stress, optical birefringence and density at the speed of 3600 m/min. The investigated relationship between optical birefringence (Δn) and stress (σ) of spinning line proposed by Hamana is, to some extent, deviated from our observation. This paper gives an empirical formulation as Δn = 13.18 × 10−3 + 6.32 × 10−10 σ with a deviation within 4%. It also provides a predicting method for controlling the change of PET structure of spinning line. Our tests have shown that the less the denier of POY single yarn, the greater the stress and crystallinity during the fiber formation, and that stress induced effect of the crystallization kinetics of PET high speed spinning is greater than that of the cooling rate.