Rayon is a manufactured regenerated cellulosic
fiber. Rayon is produced from naturally occurring polymers and therefore it is not a truly synthetic fiber, nor is it a natural fiber. It is known by the names " viscoserayon" and " art silk" in the textileindustry. It usually has a high lustre quality giving it a bright shine. Rayon contains the chemical elements carbon, hydrogen, and oxygen.
Uses of rayon
Some major rayon fiber uses include
apparel(e.g. blouses, dresses, jackets, lingerie, linings, scarves, suits, ties, hats, socks), furnishings (e.g. bedspreads, blankets, window treatments, upholstery, slipcovers), industrial uses (e.g. medical surgery products, non-woven products, tire cord), and other uses (e.g. yarn, feminine hygiene products) .
The fact that
nitrocelluloseis soluble in organic solventssuch as etherand acetone, made it possible for Georges Audemarsto develop the first " artificial silk" about 1855, but his method was impractical for commercial use. The commercial production started 1891, but it was flammable, and more expensive than acetate or cuprammoniumrayon. Because of this, production was stopped before World War I, for example 1912 in Germany.
Nathan Rosenstein invented the spunize process by which he turned Rayon from a hard fiber to a fabric. This allowed Rayon to become a popular raw material in textiles.
Paul Schützenbergerdiscovered that cellulose can be reacted with acetic anhydrideto form cellulose acetate. The triacetateis onlyFact|date=March 2008 soluble in chloroformmaking the method expensive. The discovery that hydrolyzed cellulose acetate is soluble in less polar solvents, like acetone, made production of cellulose acetate fibers cheap and efficient.
chemist Eduard Schweizerdiscovered that tetraaminecopper dihydroxide could dissolve cellulose. Max Fremeryand Johann Urbandeveloped a method to produce carbon fibers for use in light bulbs in 1892. Production of rayon for textilesstarted in 1899 in the Vereinigte Glanzstofffabriken AGin Oberbruch. Improvement by the J.P. Bemberg AGin 1901 made the artificial silk a product comparable to real silk.
Finally, in 1894,
Charles Frederick Cross, Edward John Bevan, and Clayton Beadlepatented their artificial silk, which they named " viscose", because the reaction product of carbon disulfideand cellulosein basic conditions gave a highly viscous solution of xanthate. Avtex FibersIncorporated began selling their formulation in 1910 in the United States. The name "rayon" was adopted in 1924, with "viscose" being used for the viscous organic liquid used to make both rayon and cellophane. In Europe, though, the fabric itself became known as "viscose," which has been ruled an acceptable alternative term for rayon by the U.S. Federal Trade Commission. The method is able to use wood(cellulose and lignin) as a source of cellulose while the other methods need lignin-free cellulose as starting material. This makes it cheaper and therefore it was used on a larger scale than the other methods.
Contamination of the waste water by
carbon disulfide, lignin and the xanthates made this process detrimental to the environment. Rayon was only produced as a filament fiber until the 1930s when it was discovered that broken waste rayon could be used in staple fiber.
The physical properties of rayon were unchanged until the development of
high-tenacityrayon in the 1940s. Further research and development led to the creation of high-wet-modulus rayon (HWM rayon) in the 1950s Textiles, Ninth Edition by Sara J. Kadolph and Anna L. Langford. Upper Saddle River, NJ: Prentice Hall] .
Major fiber properties
Rayon is a very versatile fiber and has the same comfort properties as natural fibers. It can imitate the feel and texture of
silk, wool, cottonand linen. The fibers are easily dyed in a wide range of colors. Rayon fabrics are soft, smooth, cool, comfortable, and highly absorbent, but they do not insulate body heat, making them ideal for use in hot and humid climates Classifications & Analysis of Textiles: A Handbook by Karen L. LaBat, Ph.D. and Carol J. Salusso, Ph.D. University of Minnesota, 2003] .
The durability and appearance retention of regular rayon are low, especially when wet; also, rayon has the lowest
elastic recoveryof any fiber. However, HWM rayonis much stronger and exhibits higher durability and appearance retention. Recommended care for regular rayon is dry-cleaning only; HWM rayon can also be machine washed .
Gallery of textures
Physical structure of rayon
Regular rayon has lengthwise lines called
striationsand its cross-section is an indented circular shape. The cross-sections of HWM and cupra rayon are rounder. rayon yarns vary from 80 to 980 filaments per yarnand vary in size from 40 to 5000 denier. Staple fibersrange from 1.5 to 15 denier and are mechanically or chemically crimped. Rayon fibers are naturally very bright, but the addition of delustering pigmentscuts down on this natural brightness .
"Regular rayon" (or "viscose") is the most widely produced form of rayon. This method of rayon production has been utilized since the early 1900s and it has the ability to produce either filament or staple fibers. The process is as follows:
#"Cellulose": Production begins with processed cellulose
#"Immersion": The cellulose is dissolved in
#"Pressing": The solution is then pressed between rollers to remove excess liquid
#"White Crumb": The pressed sheets are crumbled or shredded to produce what is known as "white crumb"
#"Aging": The "white crumb" aged through exposure to
#"Xanthation": The aged "white crumb" is mixed with
carbon disulfidein a process known as l|Xanthation, the aged alkali cellulose crumbs are placed in vats and are allowed to react with carbon disulphide under controlled temperature (20 to 30°C) to form cellulose xanthate. (C6H9O4ONa)n + nCS2 ----> (C6H9O4O-SC-SNa)n
#"Yellow Crumb": Xanthation changes the chemical makeup of the cellulose mixture and the resulting product is now called "yellow crumb"
#"Viscose": The "yellow crumb" is dissolved in a caustic solution to form viscose
#"Ripening": The viscose is set to stand for a period of time, allowing it to ripen
#"Filtering": After ripening, the viscose is filtered to remove any undissolved particles
#"Degassing": Any bubbles of air are pressed from the viscose in a degassing process
#"Extruding": The viscose solution is extruded through a
spinneret, which resembles a shower head with many small holes
#"Acid Bath": As the viscose exits the spinneret, it lands in a bath of
sulfuric acidresulting in the formation of rayon filaments
#"Drawing": The rayon filaments are stretched, known as drawing, to straighten out the fibers
#"Washing": The fibers are then washed to remove any residual chemicals
#"Cutting": If filament fibers are desired the process ends here. The filaments are cut down when producing staple fibers [http://fibersource.com/f-tutor/rayon.htm Rayon Fiber (Viscose) at fibersource.com] ]
"High Wet Modulus rayon (HWM)" is a modified version of viscose that has a greater strength when wet. It also has the ability to be
mercerizedlike cotton. HWM rayons are also known as "polynosic" or can be identified by the trade name Modal [http://ohioline.osu.edu/hyg-fact/5000/5538.html Ohio State University Rayon Fact Sheet] ] .
"Cupramonium rayon" has properties similar to viscose but during production, the cellulose is combined with
copperand ammonia( Schweizer's reagent). Due to the environmental effects of this production method, cupramonium rayon is no longer produced in the United States.
Trade names are used within the rayon industry to determine the type of rayon used.
"Bemberg", for example, is a trade name for cupramonium rayon developed by
J.P. Bembergthat is now only produced in Italydue to EPAregulations in the US [http://www.bembergcell.com/eng/index.htm BembergCell] ] .
"Modal" and "
Tencel" are widely used forms of rayon produced by Lenzing Fibers Corp.which is based in northern Austria[http://www.lenzing.com/fibers/en/textiles/4178.jsp Lenzing Fibers] ] .
"Galaxy", "Danufil", and "Viloft" are rayon brands produced by
Kelheim Fibres, a German manufacturer. [http://www.kelheim-fibres.com/service/images/viskose.pdf Kelheim Fibres] ] Acordisis a major manufacturer of cellulose based fibers and yarns. Production facilities can be found throughout Europe, the U.S. and Brazil[http://www.fibre2fashion.com/Acordis/ Acordis] ] .
"Visil rayon" is a
flame retardantform of viscose which has silica embedded in the fiber during manufacturing. [http://www.sateri.fi/in_english/visil_/ Sateri] ] .
North American Rayon Corp of
Tennesseeproduced viscose rayon until its closure in the year 2000. " [http://tennesseeencyclopedia.net/imagegallery.php?EntryID=N046 North American Rayon Corporation and American Bemberg Corporation] " in the Tennessee Encyclopedia ] . Grasimof Indiais the largest producer of rayon in the world (claiming 24% market share). It has plants in Nagda, Kharachand Harihar- all in India. [http://www.grasim.com/products/birla_viscose.htm Grasim] ] .
Art silk(artificial silk)
* [http://www.plastiquarian.com/museum/viscose/viscose03.htm History of Viscose Rayon and Artificial Silk]
* [http://www.packagingtoday.com/introcelluloid.htm Cellulose Based Plastics: Celluloid and Rayon]
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