Bulk is the most important characteristic of air-jet textured yarns. It plays a decisive role in determining the thermal and mechanical behaviour of fabrics made from these yarns and fabric comfort. Measurement of textured yarn bulk is therefore important in view of quality control. However, it is difficult to estimate bulk from the apparent diameter of air-jet textured yarns as the outer boundary of these yarns is affected by the projected loops. The bulkiness of a textured yarn is, therefore, normally measured by an indirect method. Out of the various methods proposed for measuring bulk, measurement of bulk through package density is most widely used. However, a number of variations in package density method are used for the bulk measurement. Both the textured and parent yarn packages are built to either same volume or wound for equal time on a winder. The size of the packages and winding tension affects the measured values of physical bulk.
By: Dr. V. K. Kothari and A. Mukhopadhyay
Submit Date: 6/7/2010 18:00