Woven Fabrics - Fairchild Books

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cotton or Zero Twist cotton has been used in the luxury towel industry to market terrycloth that is noticeably softer. Zero Twist is accomplished by plying a PVA (polyvinyl alcohol) yarn around the cotton yarn in the opposite direction (S direction) thus untwisting the cotton yarn. The PVA holds the cotton yarn together as it makes the pile in the terrycloth as it is woven (see p. 105). After the fabric is formed, the PVA is removed in the finishing process. The resultant towel offers consumers a very soft hand with excellent absorption. Carded and Combed Cotton Yarns Carded and combed refer to the methods used to make cotton and cotton-blend spun yarns as well as to the designation of fabrics made from such yarns. A broadcloth fabric used as shirting fabric, for example, may be carded broadcloth or combed broadcloth, depending on the yarn used. All staple fibers have to be carded to help clean and disentangle them. For less costly fabrics, the fiber is carded and formed into a thick rope of loose fiber called sliver. The sliver is made into yarn by drawing and spinning. For finer fabrics, the carded cotton in the form of sliver goes to the combing unit, which further cleans the fibers and puts them in parallel position. Combing also removes short fibers. The comb delivers a loose sliver of parallel, long fibers called combed sliver, which is used to make the spun yarns, known as combed yarns. A combed yarn thus has longer fibers, fibers in more parallel position, fibers of more uniform length, fewer speck and dirt impurities, and more uniformity of diameter than a yarn that is not combed. Fabrics of combed yarn look better, feel smoother, and are stronger and more expensive than comparable fabrics of carded yarn. Fine, lightweight yarns need to be combed because long fibers are required for proper strength. They may be found in fine shirting and luxury sheeting. For some fabrics, combed yarns are not only unnecessary, but also less desirable than carded yarns. A napped fabric, such as cotton flannel, should be made from shorter fibers to create a fuzzier surface. (See p. 205.) Denim and terry cloth are two fabrics typically made exclusively of carded yarns. This gives denim the natural, rugged look consumers recognize. The fuzzy, soft bulkiness of carding helps terry cloth remove moisture. FABRIC SCIENCE A 72 F Tow and Line Linen Yarns Linen yarns are classified into two types called tow and line. Tow linen yarn is composed of short fibers and is irregular and rather coarse in texture. Tow linen is used for coarser types of linen fabrics found in sports jackets and trousers. Line linen is composed of long fibers averaging about 15 inches (38.1 centimeters) in length. Line linen yarns are smooth and fine and are used for fabrics such as fine table linens and tissue-weight blouses. Woolen and Worsted Yarns There are two types of wool or wool-blend fabrics: woolens, made of carded yarns, and worsteds, made of combed yarns. 1 A woolen yarn is fuzzier, has a more uneven diameter, is bulkier, and has a wider range of fiber length (including short fibers) than a worsted yarn. Worsted yarn is smooth with little fuzz, has an even diameter, and is more tightly twisted and firmer than woolen yarn. (See Figure 4.6.) 1. Wool fibers are first carded and then combed as part of the worsted yarn-manufacturing process. Combed sliver of wool is called top. a b Figure 4.6 (a) Woolen and (b) worsted yarns.
Fabrics made from worsted yarn are not necessarily better than fabrics made from woolen yarn. Each kind of yarn is suitable for a specific type of fabric. Tweed is an example of a woolen fabric; gabardine is an example of a worsted fabric. There are expensive woolens as well as expensive worsteds. The following are additional facts about woolen and worsted yarns: u Fabrics of woolen yarn are more important in heavy winter coatings, ski sweaters, and blankets because woolens generally provide better insulation than worsteds. The fuzziness and soft bulkiness of woolen yarns provide the dead air spaces needed for better insulation. u Because worsted yarns are more tightly twisted than woolen yarns, fabrics of worsted yarn are usually firmer and denser than fabrics of woolen yarn. The more tightly twisted yarns help worsted to hold its pressed creases and generally to better keep its shape between cleanings than fabrics made of woolen yarn. u Fabrics made from worsted yarn usually show the yarns and weave clearly and sharply on the face of the fabric. Fabrics made from woolen yarns, on the other hand, may have a napped surface or look like the surface of felt. Worsted fabrics, such as gabardine and serge used in trousers and suiting, tend to develop a shine with wear. Because the yarns are very smooth and tightly twisted, pressure on the fabric (e.g., from sitting) and rubbing tend to flatten the yarns and produce the luster. A popular suiting fabric known as unfinished worsted is given a light napping and fulling finish, which tends to cover up the yarns (see p. 205). Thus the appearance of the yarns and the weave are more subdued and the shine problem is eliminated or greatly reduced. (Unfinished worsted is a misnomer because the fabric is, in fact, given extra finishing treatments.) Single and Ply Yarns Yarns are also categorized as single or ply. When a ply yarn is untwisted, it separates into two or more finer yarns. As shown in Figure 4.7, when a single spun yarn is untwisted, it comes apart. Ply yarn, therefore, may be defined as two or more single yarns twisted together to form one new yarn. Two-ply yarns are two singles twisted together, three-ply are three singles twisted YARNS AND SEWING THREADS A 73 F a b Figure 4.7 (a) Single spun and (b) ply yarns. together, and so forth. Most ply yarns used in clothing are two-ply. Little is gained by using yarns of higher ply. If a yarn is not ply, it is referred to as single, never single-ply. Advertisements of two-ply worsted suiting and of 2 × 2 broadcloth shirts aim to indicate quality. 2 × 2 broadcloth shirts have two-ply yarns in both warp and filling. In a 2 × 1 broadcloth, the warp is two-ply and the filling is single. In a ply yarn, two or more finer yarns are usually twisted to produce the same thickness as a single yarn, but with many additional benefits. In spun yarns, each fiber can wind more times around a thinner yarn and so hold more firmly. In plying the finer-spun yarns, more twist is added, holding the fibers more firmly in place and making the yarn stronger. Spun yarns are not perfectly even in diameter. By twisting together two or more yarns, the thin, weaker spots are reinforced. Thus, plying improves spun yarns because the fibers cannot slip as easily, the yarns are stronger, the yarn diameter is more uniform, and there is a reduced tendency to pill. Most single yarns have a Z twist. When plied with another single yarn, an S twist is used. Open end yarns (see p. 74) always have a Z twist. Ring spun (see p. 74) and air-jet (see p. 74) usually have a Z twist, but the system can produce S twist if modified.
Page 2 and 3: j.j. pizzuto’s FABRIC SCIENCE ten
Page 4 and 5: Executive Editor: Olga T. Kontzias
Page 6 and 7: Preface xv Acknowledgments xvii 1 T
Page 8 and 9: Secondary Manufactured Fibers for C
Page 10 and 11: 7 Other Types of Textiles 147 Objec
Page 12 and 13: Nonhazardous 224 Recycling 224 Work
Page 14 and 15: Fabric Performance Testing 316 Text
Page 17 and 18: air-jet bare elastic yarn blended y
Page 19 and 20: Identifying Spun and Filament Yarns
Page 21: Uses of Spun and Filament Yarns Som
Page 25 and 26: this system, one end of a fiber is
Page 27 and 28: textured yarn a b heater c d high p
Page 29 and 30: Table 4.1 Comparison oF sTreTCh Yar
Page 31 and 32: warp yarn Figure 4.14 Making chenil
Page 33 and 34: Table 4.2 Yarn number Conversions W
Page 35 and 36: Table 4.4 Thread Finishes and Their
Page 37: FABRIC SCIENCE / Swatch Kit Assignm
Page 40 and 41: Over 4,000 years ago, man created f
Page 42 and 43: yarn package yarn package yarn pack
Page 44 and 45: Figure 5.5 Various types of selvage
Page 46 and 47: the same appearance as when the fab
Page 48 and 49: More fabrics are made with plain we
Page 50 and 51: Most twills are either warp face or
Page 52 and 53: Figure 5.15 (a) Five-shaft warp-fac
Page 54 and 55: Figure 5.18 Filling-pile weave fabr
Page 56 and 57: Sometimes the pile loops are cut in
Page 58 and 59: light-pattern changes to create a r
Page 60 and 61: A product that can be considered as
Page 62 and 63: Glossary of Classic Woven Fabrics A
Page 64 and 65: Frieze: Heavy, thick, rough-surface
Page 66 and 67: Taffeta: Medium-weight, plain-weave

Woven Fabrics - Fairchild Books

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