Abstract
Extensive research on the application of supercritical CO2 dyeing (SFD) was carried out, using the commercially available filament PET yarns, with various degrees of polymerization and microstructure, in comparison with the conventional method of dyeing. After dyeing with disperse blue dyestuff (C. I. Disperse blue 60), the fibers were examined. For the SFD method, the measured value of color deepness (K/S) indicated that the higher crystallinity fiber was dyed in deeper color. This phenomenon was contradictory to the accepted theory ln dyeing. Microscopic observation of the fiber cross sectlon and measurement of dyestuff uptake into fiber, indicated that the SFD produced a deeper color. Also by the SFD, the PET with low molecular weight and/or small optical birefringence value showed high dyestuff uptake. However, by conventional dyeing, the dyestuff uptake was almost constant at any molecular weight and optical birefringence value.
