Effect of dyeing process on tensile strength properties of polyester/cotton blended yarns

Abstract

The change in the tensile strength properties of 45 Nepolyester/cotton(40/60) blended yarn after dyeing process hasbeen investigated. The tensile strength properties of the grey yarnhave also been tested for comparison. In the blended yarn, thepolyester component is first dyed with disperse dye followed bythe dyeing of cotton component with reactive dye. After dyeingboth of the polyester and cotton parts, wax based softener is usedfor finishing. It is observed that there is a significant drop intenacity of the yarn along with the gain in elongation-at-breakafter the dyeing in comparison of grey yarn. The tensile strengthproperties are investigated at three stages, viz immediately afterdyeing of polyester component, after dyeing of cotton componentand then after the application of softener. It is found that the dropin tenacity of the yarn after dyeing of cotton part is much higherthan the drop found immediately after polyester dyeing. The valueof elongation-at-break has increased very significantly afterdyeing of polyester component. The elongation-at-break dropsafter dyeing of cotton component but remains always higher thanthe grey yarn. The softener application also plays a role in drop oftenacity and increase in elongation-at-break.