Chapter 15 Yarn Properties..pptVIP

Ch.15 Yarn Properties In traditional textile manufacturing, it has been common to first make yarn from fibers, then produce a fabric from the yarn. Fabrics produced directly from fibers (skipping the yarn step) represent a growing textile market segment, but traditional woven and knitted fabrics produced by intertwining（捻合，缠结） yarns still dominate the market. In addition to knitting yarns and weaving yarns, sewing threads, twine（绳，股线） for wrapping（包装） packages, and the rope（缆绳） used to tie a sailboat to the dock are made by combining fibers. Basic Terminology ASTM D 123 defines yarn as a continuous strand[（绳、线的）股；缕；单纱，须条，绞合] of textile fibers, filaments, or material in a form suitable for knitting, weaving, or other-wise intertwining(捻合，缠结) to form a textile fabric. Yarn structures used for purposes other than fabric production may be referred to as cords（细绳，粗线), ropes（绳索） and thread（线）. Thread is a specific term for yarn used to join fabrics by the process sewing。 When short-staple fibers are twisted together by the process of spinning, the product may be referred to as a staple （短纤维） or spun yarn （短纤维）. Other binding mechanisms, such as wrapping short fibers with a continuous filament or using an adhesive to bind fibers together, are also used: their products also referred to as spun yarns. A single spun strand, produced by one of the processes above, is referred to as a singles yarn（单纱，单丝). When two or more single strands are combined, the yarn becomes a ply yarn（股线） , with each single strand referred to as a ply. It is possible to combine filaments and spun strands to form more complex yarns. Many types of strands may be combined to form novelty（新奇的、新颖的） yarns for design interest in a fabric, or several simple strands may be combined to provide strength. A classification system for yarns is shown in Table 15.1. YARN SIZE The concept of relating linear density to the fineness of a textile strand was introduced with the discussi