High-Speed Melt Spinnability, Structural and Physical Properties of a Low Melting Copolyester Multifilament Yarn

Hypothesis: 

Fibers with low melting point have high bonding strength with other fibers, and in addition, they have a controllable melting temperature and good processability. Currently, these fibers are used in production of non-woven fabrics for textile, medical and agricultural applications. In this study, melt spinnability of two grades of low melting point co-polyester in high speed spinning has been investigated. Also, structural, rheological and physical properties of the resulting filament yarn have been studied.

The properties of polymeric chips were investigated, and for this purpose, differential scanning calorimetry analysis, melting point determination test, drying conditions and rheological analysis were carried out. Then filament yarns produce, and their properties were investigated. Linear density, yarn tensile properties, melting temperature, thermal shrinkage, rheological properties, X-ray diffraction, differential scanning calorimetry, optical birefringence index and surface longitudinal cross-section were analyzed.

The results of thermal analysis of polymeric chips with low melting point analysis showed that the used polymers are not crystalline and their melting point is about 176°C. The temperature 60°C for 24 h is enough to dry the chips, and the melt of these materials has a viscous behavior. Both low melting point co-polyesters grades were spun by melt spinning process. But only one of them had a suitable spinnability. After melt spinning, as-spun yarns were drawn because it was necessary to produce no brittle filaments. The results of the investigation of the properties of as-spun and drawn yarns showed that the best conditions for melt spinning of the copolyester yarn is as follows: the optimum extrusion temperature of 230°C and the take-up speed of 2500 m/min. All samples have no crystalline region, the polymer chains are oriented, and the phenomenon of rheological instability, such as melt fracture during melt spinning, which disrupts the cross-sectional area of the fibers, has not occurred.