Single Thread Shrinkage of Polymer Treated Wool Fabrics

Abstract

Single thread shrinkage in two light-weight, plain weave wool worsted fabrics has been studied with a range of shrink-resist polymer treatments that depend on an interfiber-bonding mechanism, with different finishing treatments before polymer ap plication, and with a selection of wash tests. Single thread shrinkage generally developed from thicker than normal yams, but not all thick yams developed single thread shrink age. A staining test showed that polymer was lost more readily during washing from the thicker yam sections. It was difficult to study single thread shrinkage quantitatively, and it was necessary to make comparisons at the same level of area shrinkage, since the number of single thread shrinkage spots increased as washing progressed. The number of spots per unit area in samples washed to 10% area shrinkage varied with the polymer applied, and for one polymer treatment, the spots decreased with increasing polymer concentration. The number of single thread shrinkage spots on warp and weft yarns was different. One recommendation examined to alleviate single thread shrinkage was to pressure decatize fabrics before polymer application. Such fabrics showed improved shrink resistance with Synthappret BAP but not with other polymers. The pressure decatization did not remove single thread shrinkage; instead it was nec essary to wash treated samples for a much longer period before it became apparent.