Rayon spun yarn

Spun Yarn. After rayon became established in the textile industry, where it could be used as a silklike fiber, and its selling price was greatly... 

The spun yarns used in textile fields are prepared mainly by the cotton or rayon staple fiber-spinning systems. The spun yarns used in the industrial field are produced mainly by the... 

Sunn has been grown in India since prehistoric times [44]. The plant is used not only for fiber but also for green manure. The fiber is used locally to make fishing twines, thick canvas, cordage, ropes, and other items a fair portion of the fiber is also exported. The use of sunn for ehemical pulp and for viscose rayon has been explored [39]. Attempts are also made to blend it with other fibers to produce ring spun yarns, presumably for clothing applications [48] India (186,624 MT), Thailand (57,000 MT), China (44,000 MT), and the former Russian Federation (48,000 MT) in 2003 were the largest produeers of the so-called jutelike fibers as well as sunn [FAO database]. 

Pot spinning n. A method formerly used for making viscose rayon. The newly spun yarn was dehvered into the center of a rapidly rotating, centrifugal pot, where it received twist and centrifugal force caused it to go to the wall of the pot. The yarn package so formed was called a cake. 

Even when crimp is fully developed it is easy to pull out (low energy) and difficult to translate into noticeably bulkier woven and knitted fabrics. It does however improve the absorbency and the cohesion of the staple (important in spun-yarn and nonwoven making) and gives a subtly different texture to woven fabrics. Coarse crimped rayon was the leading synthetic carpet fiber in Europe in the 1960s, but has since been replaced by the highly durable bulked continuous filament nylon yams. Crimp is most important in rayon used for hygienic absorbent products. 

Combination Fabric n A fabric containing (1) different fibers in the warp and filling (e.g., a cotton warp and a rayon filling), (2) ends of two or more fibers in the warp and/or filling, (3) combination yarns, (4) both filament yarn and spun yarn of the same or different fibers, or (5) filament yarns of two or more generic fiber types. Combination fabrics may be either knit or woven. They should not be confused with blend fabrics. Although blend fabrics also contain more that one fiber, the same intimately blended spun yarn is present in both warp and filling. 

Rayon was first made by denitration of cellulose fibers (Chardonnet process). The cellulose was first reacted with a mixt of nitric and sulfuric acids to form NC, The prod was then dissolved in a mixt of eth and ethanol and spun into yarn by a "dry spinning process. In some instances the yarn was denitrated by alkaline hydrosulfites, neutralized and then w washed and dried (Ref 9). See also under "Cellulose Nitration, Denitration in Vol 2, C118-R to C119-R... 

The primary fabrication process in the production of synthetic fibers is the spinning—i.e., the formation—of filaments. In every case the polymer is either melted or dissolved in a solvent and is put in filament form by forcing through a die, called spinneret, having a multiplicity of holes. Spinnerets for rayon spinning, for example, have as many as 10,000 holes in a 15-cm-diameter platinum disc, and those for textile yarns may have 10-120 holes industrial yarns such as tire core might be spun from spinnerets with up to 720 holes. 

Yarns for tire cords are mostly spun 1650 den/1100 filaments twisted into two-ply cords, although other weight yarns are used for various purposes. Since 1965, rayon has gradually lost its prominence in this field, first to nylon and then to polyester. However, rayon s... 

Continuous-filament (regular) rayon is produced by either the cuprammonium or viscose process. Both are supplied as yarn having a high sheen resembling silk. End uses include those applications where durability and dimensional stability are not particularly important. Cuprammonium fibers can be spun in finer deniers than viscose fibers, and they find a market for ladies shawls, scarves, blouses, coat linings, etc. The amount of cuprammonium fiber produced is quite small relative to viscose rayon. 

Desulfurizing ( )de- sol-for- Iz-er) vt. An after treatment to remove sulfur from newly spun viscose rayon by passing the yarn through a sodium sulfide solution. 

Douppioni n. A rough or irregular yarn made of silk reeled from double or triple cocoons. Fabrics of douppioni have an irregular appearance with long, thin slubs. Douppioni-like yarns are now being spun from polyester and/or rayon staple. 

Synthetic cellulose yams were developed between 1880 and 1910, first from a nitrocellulose solution, and later as copper rayon and "viscose rayon . The cellulosics are often called half-synthetic because the raw material is a natural polymer. The most important fully synthetic yarns were developed between 1935 and 1942 - polyamides (PA66, PAG), polyester (PET), and acrylic yarns (PAN copolymers). Another half-century later, many high-performance fibers were introduced, for example aramid (PPTA), gel-spun polyethylene, and carbon fiber. 

The spinning solutions - caustic plus acid - are highly corrosive. The spinnerets are made of gold/platinum, round, with diameters of a few centimeters only. The capillaries are small (50-75 gm) and close to each other (< 1 mm). The number of holes must be large because the standard filament titer of rayon yarns is around 1.7 dtex. The freshly spun filaments are very weak and a tube is often placed around the spinning bundle. 

This twisting could have been carried out in the same plant where the yarn was spun, but the existence of silk throwsters (from the Anglo-Saxon thrawan, to twist or revolve) made that unnecessary. However, as the rayon industry developed, the amount of yam twisted in the producing plant or sent forward to throwsters decreased. Over the years the trend has been to use less twist and to place, instead, several thousand parallel ends directly on a beam, to form packages weighing as much... 

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