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Filament yarns are made from long, continuous strands of fiber. Monofilament yarns, those made from a single filament, find limited use in nylon hosiery (where an exceptionally sheer fabric is wanted), in some open-work decorative fabrics, and in fabric webbing (used in some lightweight beach or casual furniture) as well as in a variety of industrial uses. More commonly, many filaments are joined to form multifilament yarns. Multi-filament yarns can be made more cohesive by twisting them together loosely or more tightly. The amount of twist together with the characteristics of the fibers (luster, hand, cross-sectional shape, etc.) will determine the appearance and feel of the yarn. For example, a loosely twisted smooth filament yarn made from a bright fiber would be characterized by marked luster, resistance to pilling, and a smooth surface. Sometimes filament yarns are put through an additional process called texturing. Texturing modifies the feel and bulk of filament yarns.
Staple, or spun, yarns are made from staple length fibers. Being short, staple fibers must be held together by some means in order to be formed into a long, continuous yarn. Although the multiple processes required to make staple yarn add significantly to the cost of the yarn, the aesthetic qualities such as comfort, warmth, softness, and appearance make these yarns highly desirable in many products. Natural fibers, except for silk, are all staple fibers. Silk and manufactured fibers can be cut or broken into staple fibers, so that it is possible to spin any natural or manufactured fiber into a staple yarn. In addition to identifying yarns as being made from either filament or staple fibers, yarns are also classified based on a number of other characteristics. Authorities often differ when they define yarn types. The following are the most common classifications.
Yarns Classified By Number Of Parts
Yarns that have been classified by the number of parts they possess are divided into single, ply, and cord yarns. A single yarn is made from a group of filament or staple fibers twisted together. If a single yarn is untwisted, it will separate into fibers. A single yarn might be identified as either a single yarn of staple fibers or a single yarn of filament fibers.
Ply yarns are made by twisting together two or more single yarns. If ply yarns are untwisted, they will divide into two or more single yarns, which, in turn, can be untwisted into fibers. Each single yarn twisted into a ply yarn is called a ply. Cord yarns are made by twisting together two or more ply yarns. Cord yarns can be identified by untwisting the yarn to form two or more ply yarns. Cord yarns are used in making ropes, sewing thread, and cordage and are woven as decorative yarns into some heavyweight novelty fabrics.
Yarns Classified By Similarity Of Parts
Simple yarns are those yarns with uniform size and regular surface. They have varying degrees of twist, ranging from loose to moderate, tight or hard twist. Single, ply and cord yarns can all be simple yarns if their components are uniform in size and have a regular surface. When one strand of fibers is twisted together evenly, it is classified as a simple single yarn. Two simple, single yarns twisted together create a simple ply yarn. Yarns made to create interesting decorative effects in the fabrics into which they are woven are known as novelty yarns. Some authors also call these yarns complex yarns, although complex yarns usually have more than one part. Novelty yarns can be single, ply, or cord, staple or filament. Novelty yarns are used in knitted sweaters and dresses, contemporary drapery and upholstery fabrics, and the decoration of men’s and women’s suiting fabrics. In the industry novelty yarns tend to be referred to as fancy yarns. Terminology identifying these yarns is confusing. The following list of terms and their definitions represents an attempt to define these terms as they appear to be accepted by most authorities.
- Boucle yarns are ply yarns. An effect yarn (so-called because it is used to create decorative effects) forms irregular loops around a base yarn or yarns. Another yarn binds or ties the effect yarn to the base. Ratine yarns are similar to boucle in construction. The loops in ratine yarns are spaced evenly along the base yarn. Snarl yarns are another type of loop yarn in which two or more single yarns under different tension are twisted together. The varying tension allows the effect yarn to form alternating unclosed loops on either side of the base yarn.
Flake, flock, or seed yarns are made of loosely twisted yarns that are held in place either by a base yarn as it twists or by a third or binder yarn. These yarns are relatively weak and are used in the filling to achieve decorative surface effects.
Nub yarns are ply yarns in which an effect yarn is twisted around a base yarn a number of times in a small area to cause an enlarged bump or “nub.’ Sometimes a binder yarn is used to hold the nubs in place. The spacing of the nubs may be at regular or irregular intervals. Nubs are often different colors than the base yarn. The terms knot, spot, or knop are also applied to this type of yarn.
Slub yarns maybe either ply or single yarns of staple fibers. The slub effect is created by varying the twist in the yarn, allowing areas of looser twist to be created. This produces a long, thick, soft area in the fabric called a slub. Slub yarns are irregular in diameter. The surface of fabrics woven with slub yarns shows these irregularities. Yarns made in this way have areas of varying twist, causing weaker areas in the yarn. In many fabrics slub yarns are placed in the filling or crosswise direction where fabrics receive less strain. Slubs are the same color as the rest of the yarn and cannot be pulled out of the fabric without damaging the structure of the fabric. Filament yarns can be spun with varying degrees of twist. These yarns also create a slubbed appearance in fabrics. Such filament yarns are known as thick-and-thin yarns.
Spiral, or corkscrew, yarns are made of two plies, one soft and heavy, the other fine. The heavy yarn winds around the fine yarn..
Chenille yarns are made by a totally different process and require several steps in their preparation. First, leno-weave fabric is woven. This fabric is cut into strips, and these strips, which have a soft pile on all sides, are used as yarns.