Investigation of air-jet texturing behaviour of PET and PBT yarns

In this study, polyethylene terephthalate (PET) and polybutylene terephthalate (PBT) yarns with the same yarn count and filament number were subjected to air-jet texturing process. Texturing was carried out with 3 different overfeeds (20%, 40% and 60%) and 4 different mechanical stretch ratios (0%, 2%, 4%, 6%). In addition, the effect of the heat-setting was also analysed. The air-jet texturing behaviour of these two yarns, which are consist of different raw materials, was investigated with the help of yarn count determination, tensile tests, optical microscope analyses and elastic recovery tests. As a result, depending on the production parameters used in the study, air-jet textured PET, and PBT yarns gave different loop structures at the same overfeed and mechanical stretching ratios. The differences in their texturing behaviours were directly caused by their raw material (polymer structure). The mechanical stretch ratio significantly influenced the looped structure of the yarn. The most looped structure was obtained at different mechanical stretch ratios for each overfeed. In general, yarn count, elongation and instability values were increased, and the tensile strength was decreased with the increase in the looped structure.