HEAT SETTING OF POLY(BUTYLENE TEREPHTHALATE)

Poly(butylene terephthalate) (PET) yarn was subjected to heat setting at different temperatures for various time periods under taut conditio ns. Properties such as breaking load, critical dissolution time, dyein g with disperse dyes, etc. were evaluated and related to the changes t aking place in the internal fiber structure. A temperature of about 14 0 degrees C and a time period of about 60 seconds was found to be opti mum for attaining the dimensional stability without affecting the usef ul textile properties of PET filament yam significantly.