Structure of High Stretch Yarns and Their Tensile Properties

Abstract

To clarify the structure of high stretch yarns in helical coils, various photographs of them and of other textured yarns or models are taken, and the relation between their tensile properties and the structure is studied. Results obtained are:1. Hard-twist two-ply yarns are studied as a model having two first twists per one pitch. They have hollow parts in the center of the yarn, and the radius can be expressed by: a=0.896 2. We have explained the configuration of the crimps or loops of the constituent filaments when hard-twist two-ply yarns are twisted, heat-set and untwisted. 3. We have found that the tensile properties of high stretch yarns are dependent on the configuration of the constituent filaments and on the complexity of assembly of these filaments, and that the fundamental shape of crimps of the yarn consists of a series of rings which develop the high extension property.