DYEING OF POLY (ETHYLENE TEREPHTHALATE) PRE-TREATED WITH SOLVENTS

Abstract

The amorphous contents in poly (ethylene terephthalate) (PET) films pre-treated with 18 kinds of solvents at 106-135°C for 3hours were determined by means of an infrared spectrophotometer. Approximately linear relationships were found between the amorphous contents in PET films and the shrinkage of PET filament yarns, or birefringences of PET films, respectively.
Partition coefficients, diffusion coefficients and saturation values of Disperse Red 15 for the above pre-treated PET films were measured in iso-octane dye baths at 85-105°C, and correlated with the amorphous contents in the above PET films. These values increased approximately linearly with the amorphous contents. In particular, pre-treatment with solvents of which solubility parameter were around 10 or 12 gave higher values of partition coefficients, diffusion coefficients and saturation values.
Heats of dyeing increased approximately linearly with the amorphous contents. However, activation energies for diffusion of dyes and energies required to make a path which dyes molecules moved through, decreased linearly with the amorphous contents.
Dyeing properties of Disperse Red 15 on the PET films were dependent on the pre-treatment temperature even for the same amorphous contents of the films. The present results show that amorphous regions of PET having the same amorphous contents may be structurally different in certain cases.