YARN DEFORMATION IN BENT FABRIC

Abstract

In order to investigate the bending mechanism of twistless yarn fabric, which is related closely to the hand properties, the deformation of yarn in the fabric by bending were observed in detail on both twistless and twisted fabrics.Materials and yarn making method are the same as those used in the previous reports. Yarn density in fabrics is shown in Table 1, in which No.1_??_No.7 are twistless yarn fabrics, and No.8_??_No.14 are twisted yarn fabrics.Some microscopic photographs are demonstrated in Fig. 1 and Fig. 2. From these results, yarn deformation in bending can be fully observed.The changes of yarn packing factor by bending are shown in Fig. 11_??_Fig. 14. These figures show that the yarn packing factors of twistless yarn fabrics change more drastically in slight bending stages to ρ=5cm-1 (ρ: curvature) than those of the twisted yarn fabrics. In final stages where ρ=20cm-1, however, the packing factors in both fabrics become almost the same value. In twistless yarn fabric, the packing factor change in the lower yarn density is larger than that in the higher yarn density. Generally, inside yarns have larger changes in the yarn packing factor than outside yarns. Comparing with the conventional twisted yarn fabrics, the twistless yarn fabrics have a characteristic to respond easily to the external force. This characteristic is due to the movable property of constituting fibers, and is closely related to “softness” or “fullness” of twistless yarn fabrics.