The effect of process conditions, temperature, time and rate of temperature rise, on the exhaustion of disperse dye on polyester yarn under High-Temperature dyeing conditions was investigated. Two ply spun type Dacron 54 polyester yarn was dyed with Disperse Red 60 in 0.5 g/l dye bath concentration using an Ahiba Texomat Dyeing Apparatus under High-Temperature Dyeing conditions. The dyeing process design used, consists of three levels of dyeing temperature (105°C, 120°C, 135°C), four levels of holding time (0 min, 15 min, 30 min, 60 min) and two levels of rate of temperature rise (1ºC/min, 3°C/min). After the dyeing process, the dye concentration in the yarn was obtained through extraction and measured spectrophotometrically. A factorial analysis of variance (ANOVA) test was used to determine whether or not significant differences existed among dyeing process conditions in regard to the dye uptake of the yarn. If significant differences existed, which parameter of process conditions (temperature, time, rate of temperature rise or their interactions) was responsible.

The results of this study indicated that a three-way interaction of temperature, time, and rate of temperature rise was responsible for the differences in dye uptake of the yarn. The dye uptake of the yarn increased by increasing dyeing temperature from 105°C to 120°C for all levels of holding time and rate of temperature rise. However, increasing dyeing temperature from 120°C to 135°C, did not increase dye uptake of the yarn. The dye uptake of the yarn increased by increasing holding time from zero to 15 minutes for dyeing temperature of 120°C. However, increasing holding time from 15 to 60 minutes, did not increase dye uptake of the yarn. At the dyeing temperature of 120°C, a slower rate of temperature rise resulted in greater dye uptake of the yarn. It can be concluded that high temperature dyeing of polyester yarn at 120°C for 15 minutes with a rate of temperature rise of 1°C/min was the optimum dyeing process in achieving full exhaustion.