Experimental study on dyeing technical PET yarns having different TiO2 contents

TiO2 contents in yarns can influence color yield so that dyeing quality of industrial poly ethylene terephthalate (PET) yarns can be improved through the adjustment of TiO2 contents. To evaluate the dyeing performance of color yield, the chips which included the different TiO2 contents of 330, 550, and 1,100 ppm respectively were used to produce the yarns of different TiO2 content by a spin-draft machine. The physical and structural properties of the yarns were measured to investigate effect of the TiO2 contents on them. Dye uptake and dyeing rate were also evaluated using a colorimeter to compare the yarns having different TiO2 contents. The experimental results showed that there were no appreciable variation in physical and structural properties among the yarn samples and no difference were observed among the dyed fabric samples with regard to dyeing uptake and dyeing rate. However, the color yield of dyed fabrics increased as TiO2 contents decreased in the yarns especially when the fabric samples were dyed to pale shade. The physical reasoning could be proposed on why the yarns having low TiO2 contents appeared to have higher color yield after dyeing.