Relaxation Annealing After Drawing
topic
Drawn yarn relaxation uses a heated godet zone after drawing with controlled overfeed of 2 to 8 percent that allows the drawn yarn to contract under defined tension while at elevated temperature, reducing thermal shrinkage from 8 to 15 percent in unrelaxed yarn to below 3 to 5 percent in relaxed drawn yarn, with relaxation temperature and overfeed governing the degree of residual thermal shrinkage reduction that determines fabric stability in downstream thermal processing.
Role
Reduces the residual thermal shrinkage potential of drawn synthetic yarns through controlled thermal relaxation that allows partial molecular orientation loss in a controlled manner before the yarn is wound and used in fabric production, preventing the uncontrolled shrinkage that unrelaxed high-tenacity drawn yarn would undergo during dyeing and finishing heat treatments that would distort fabric dimensions unacceptably.