Structure change of self-crimping bi-component filament after dyeing and finishing process and its elasticity

The purpose of this study was to investigate the apparent performance of different self-crimping bi-component filament fabrics during finishing and the elasticity of their end-products. Therefore,three kinds of PTT / PET self-crimping bi-component filaments made by different factories were woven,dyed and finished under the same process conditions and then compared with polyurethane fiber fabric. The weight reduction rate,weft shrinkage,elastic elongation and elastic recovery percentage of the above four kinds of fabrics were obtained. The results indicated that with the increase of DPF,the weight reduction rate decreases but the weft shrinkage increases. The weight reduction rate decreases as the fabric count increases. The elastic recovery decreases as the elastic elongation increases. Optical microscopy,scanning electron microscopy and differential scanning calorimetry( DSC) examinations showed that due to the finer DPF and larger specific surface area,one kind of PTT / PET filament exhibited separation of the two components resulting from caustic corrosion during the process of dyeing and finishing and hence the high elasticity inherent in bi-component filaments was lost.