Rayon is an artificial fiber made from regenerated cellulose fibers. Many types and levels of rayon can mimic the flavors and textures of natural fibers such as silk, wool, cotton, and linen. The types that resemble silk are often called artificial silk.
Rayon is made of pure cellulose, mainly from wood pulp, which is chemically converted to a soluble compound. It is then dissolved and forced through the spinneret to produce chemically compacted filaments, resulting in virtually pure cellulosic fibers.
Because rayon is made from natural polymers, these fibers are considered semisynthetic fibers, whereas the proper use of synthetic fibers is sometimes used for fully synthetic fibers. Specific rayon types include viscose, capital and lyocell, each different in the manufacturing process and the properties of the finished product.
Workers can be seriously disadvantaged by the carbon disulfide used to make most of the rayon.
Video Rayon
Rayon dan variasinya
Nitrocellulose
The solubility of nitrocellulose in organic solvents such as ether and acetone was the basis for the first "artificial silk" by Georges Audemars in about 1855. Although chemically different from rayon, cellulose was successfully dissolved even with chemical modification. Commercial production began in 1891, but the results were flammable and more expensive than cellulose acetate or rayon cuprammonium. Because of this cost, production ceased in the early 1900s. Nitrocellulose is briefly known as the "mother-in-law silk". Frank Hastings Griffin invented the double godet, a special spinning process that turns artificial silk into rayon, making it usable in many industrial products such as tires and clothing. Nathan Rosenstein discovered the "spunize process" by which he transformed the rayon from hard fibers into fabrics. This allows rayon to become a popular raw material in textiles.
Acetate
Rayon should not be confused with acetate (cellulose acetate) or triacetate. These terms are often used interchangeably in the past but are now different. While rayon reconstitutes natural cellulose polymers, the older acetate process reacts cellulose with acetic anhydride to form cellulose acetate. Furthermore, rayon production requires carbon disulfide as a solvent while acetate uses a much safer solvent such as acetone. However, rayon is a fiber that is stronger than other similar acetates, and has dominated.
Cuprammonium Method
Swiss chemist Matthias Eduard Schweizer (1818-1860) found that cellulose was dissolved in tetraaminecopper dihydroxide. Max Fremery and Johann Urban developed a method for producing carbon fiber for use in light bulbs in 1897. Production of rayon cuprammonium for textiles began in 1899 at Vereinigte Glanzstoff Fabriken AG in Oberbruch near Aachen. Improvements by J. P. Bemberg AG in 1904 made artificial silk a product comparable to real silk.
Viscose Method
The English chemist Charles Frederick Cross and his colleagues, Edward John Bevan and Clayton Beadle, patented their artificial silk in 1894. They named their material "viscose", because its production involved a very thick intermediate solution. The process builds upon a strongly alkaline cellulose reaction, followed by treatment of the solution with carbon disulfide to provide an xanthate derivative. The xanthate is then converted back into cellulose fibers in the next step. The first commercial viscose Rayon was produced by the British company Courtaulds Fibers in 1905. Courtaulds formed the American division, American Viscose, (later known as Avtex Fibers) to produce their formulations in the United States in 1910. The name "rayon" was adopted in 1924, with "viscose" is used for viscous organic liquids used to make both rayon and cellophane. In Europe, though, the fabric itself is known as "viscose", which has decided an acceptable alternative term for rayon by the US Federal Trade Commission (FTC).
Viscose methods can use wood as a source of cellulose, while other pathways to rayon require lignin-free cellulose as the starting material. The use of woody cellulose sources makes viscous cheaper, so it is used on a larger scale than other methods. On the other hand, the viscose process provides a large amount of contaminated wastewater. Rayon was produced only as filament fibers until the 1930s, when a method was developed to utilize "rayon damaged waste" as staple fiber.
The physical properties of rayon remained unchanged until the development of high-powered rayon in the 1940s. Further research and development led to high-wetulus rayon (HWM rayon) in the 1950s. Research in the UK is centered on the government-funded British Rayon Research Association.
The rayon industrial application emerged around 1935. Replacing cotton fibers in tires and belts, the rayon industry type developed a completely different set of properties, among which tensile strength (elasticity) is paramount.
Lyocell
The Lyocell process relies on the dissolution of cellulosic products in a solvent, N-methylmorpholine N-oxide. The process begins with a woody cellulose source and involves spinning dry-wet jet. It was developed in American Enka and Courtaulds Fibers who are now dead. In 2013, Tencel's Lenzing brand is probably the most famous lyocell fiber producer.
Capital
Capital is a type of rayon, a semi-synthetic cellulose fiber made by reconstituted cellulose, in this case often from beech trees. Capital is used alone or with other fibers (often cotton or spandex) in clothing and household items such as pajamas, underwear, bathrobes, towels, and bed linens.
Capital is processed under different conditions to produce stronger and more stable fibers when wet than standard rayon, but has a soft feel, similar to cotton. It can fall dry without damage due to the increase in its molecular alignment. These fabrics are known to contain less than cotton due to the lower fiber properties and friction surfaces.
Micro-Capital is a variant of Textile Capital. The material is softer than cotton and has desirable properties that include higher resistance to moisture depreciation and moisture.
Maps Rayon
The properties of the main fiber
Rayon is a versatile fiber and is widely claimed to have the same comfort properties as natural fibers, although the hanging and slickness of rayon textiles is often more like nylon. It can mimic the shades and textures of silk, wool, cotton and linen. The fiber is easily dyed in various colors. Rayon fabric is soft, smooth, cold, comfortable, and highly absorbent, but does not block body heat, making it ideal for use in hot and humid climates, although it also makes their hands "cold" and sometimes almost slimy to the touch.
The durability and appearance retention of rayon viscose is usually low, especially when wet; also, rayon has the lowest fiber elastic recovery. However, HWM rayon (high-wet-modulus rayon) is much stronger and shows higher endurance and retention of appearance. The recommended treatment for regular viscose rayon is dry-cleaning only. HWM rayon can be washed by machine.
Rayon industrial yarns outperform polyester and are manufactured for belts with high performance tires (eg Cordenka, Germany).
Texture gallery
Physical structure
Ordinary rays have elongated lines called striations and their cross-shaped cross-section. The cross section of HWM and cupra rayon are more rounded. The rayon filament yarn varies from 80 to 980 filaments per yarn and varies in size from 40 to 5000 denier. Staple fibers range from 1.5 to 15 denier and are mechanically or chemically wrinkled. The rayon fiber is naturally very bright, but the addition of a shrinking pigment reduces this natural brightness.
Production method
Ordinary light (or viscose ) is the most widely produced form of rayon. This method of rayon production has been in use since the early 1900s and has the ability to produce filaments or staple fibers. The process is as follows:
- Cellulose : Production begins with processed cellulose (obtained from wood pulp and plant fiber).
- Immersion : Cellulose is dissolved in caustic soda: (C 6 H 10 O 5 ) n n NaOH -> (C 6 H 9 O 4 ONa) n n H 2 O
- Pressing : The solution is then pressed between the rollers to remove the excess fluid
- White Crust : A cracked or shredded pressed sheet to produce what is known as "white crumbs"
- Aging : "White crust" is old through oxygen exposure
- Xanthation : "old" white crumbs mixed with carbon disulfide in a process known as Xanthation, old alkaline cellulose crumbs placed in vats and allowed to reacts with carbon disulfide under controlled temperature (20 to 30 ° C) to form cellulose xanthate: (C 6 H 9 O 4 ONa ) n n CS 2 -> (C 6 H 9 O-SC-SNa n
- Yellow Crumb : Xanthation alters the chemical makeup of the cellulose mixture and the resulting product is now called "yellow crumb"
- Viscose : "yellow crumb" is dissolved in caustic solution to form viscose
- Maturity : Viscose is set to stand for a certain period, allowing it to mature: (C 6 H 9 O 4 O-SC-SNA n n H 2 O - > n
n /span> CS 2 n NaOH - Filtering : After cooking, viscose is filtered to remove insoluble particles
- Dimming : The air bubble is pressed from the viscose in the degassing process
- Extrusion : The viscose solution is extruded through a spinneret, which resembles a shower head with many small holes
- Acid Bath When the viscose exits the spinneret, it enters the bath of sulfuric acid, resulting in the formation of rayon filaments: (C 6 H 9 O 4 O-SC-SNa n 1 < span>/ 2 n H 2 SO 4 -> (C < sub> 6 H 10 n CS n 2 1 / 2 n Na 2 SO 4
- Drawing : Filament rayon stretched, known as picture, to straighten fibers
- Washing : The fibers are then washed to remove the remaining chemicals
- Cut : If the filament fiber is desired, the process ends here. Filaments are cut when producing staple fibers
High wet rayon modulus (HWM) is a modified version of viscose that has more power when wet. It also has the ability to mercerized like cotton. HWM rayon is also known as "polynosic". Polynosic fibers are dimensionally stable and do not shrink or are pulled out of shape when wet like a lot of rayon. They are also wear resistant and strong while maintaining soft and smooth shades. They are sometimes identified with the Capital trade name.
High-tenacity rayon is another version of the viscose that has almost twice the strength of HWM. This type of rayon is usually used for industrial purposes such as tire straps.
Cuprammonium rayon has properties similar to viscose but during production, cellulose is combined with copper and ammonia (Schweizer reagents). Due to the environmental effects of this production method, the rayon cuprammonium is no longer produced in the United States.
Producing health hazards
See also Viscose # Pollution and harm to workers
Highly toxic carbon disulfide is used in viscose production, which causes many incidents and legal cases. However, volatile carbon disulfide is lost before rayon reaches the consumer; rayon itself is essentially pure cellulose. Studies from the 1930s show that 30% of American rayon workers suffered severe effects. The defect rate in modern factories (especially in China, Indonesia and India) is unknown.
Disposal and biodegradability
The biodegradability of various fibers in soil burial and sewage sludge was evaluated by Korean researchers. Rayon is found to be more biodegradable than cotton, and cotton is more than acetate. The more water resist the rayon-based fabric, the slower it will decompose. Silverfish can eat rayon.
A recent ocean survey found that rayon accounted for 56.9% of the total fiber found in deep ocean, the rest being polyester, polyamide, acetate, and acrylic.
Alternative for cotton
Rising cotton prices in 2010 caused clothing makers to start replacing cotton with rayon in their fabric. As demand for rayon increases, companies like Fortress Paper have invested in pulp mills to increase production. Rayon now sells for $ 2.70 per pound, which has led to an increase in retail prices of clothing made with rayon, but rayon has a price advantage over cotton.
Mislabelling
See also Bamboo textiles
In 2010, the US Federal Trade Commission issued a letter informing more than 100 companies that they mis-distinguished rayon products as being made of bamboo, deceiving environmentally conscious consumers. In 2015, the FTC filed a complaint against Bed Bath & amp; Outside, Nordstrom, J.C. Penney, Backcountry.com, and their subsidiaries, continue to cheat selling rayon that is misconstrued as bamboo. The four companies are required to pay civil penalties of US $ 1.3 million for violating "Textile and Textile Rules Act" and Section 5 (m) (1) (B) of the FTC Act. A similar action took place in Canada.
Impact on the US textile industry
Rayon contributed in part to the decline of the US textile industry in the 1920s. It's much cheaper to produce than wool, cotton, or silk. It also requires less processing and therefore fewer workers. In addition, it was 50% cheaper than silk during the 1920s in the US. Later, it was used initially for men's socks but later for underwear and ladies stockings.
Producer
Trade names are used in the rayon industry to label rayon types in products. Viscose Rayon was first produced in Coventry England in 1905 by Courtaulds.
Bemberg is the trade name for cupramonium rayon developed by J. P.Bemberg. Bemberg performs like a viscose but has a smaller diameter and closer to silk. Bemberg is no longer produced in Italy, but is still produced in Japan, due to US Environmental Protection Agency regulations in the US. Fibers are smoother than rayon viscose.
Capital and Tencel are rayon forms widely used by Lenzing AG. Tencel, the generic name lyocell , is made by a slightly different solvent recovery process, and is considered a different fiber by the US FTC. Tencel lyocell was first commercially produced by the Grimsby Courtaulds factory in England. The process, which dissolves cellulose without chemical reactions, was developed by Courtaulds Research.
Accordis is a major producer of fiber and cellulose based yarns. Production facilities can be found throughout Europe, the US and Brazil.
Visil rayon is a flame retardant form of viscose that has silica embedded in the fibers during the manufacturing process.
Rayon Corporation of Tennessee in North America produced viscose rayon until closure in 2000.
Grasim of India is the largest rayon producer in the world (claiming 24% market share). It has plants in Nagda, Kharach and Harihar - all in India, as well as joint ventures in Canada, Laos and China.
See also
- Viscose
- Cellophane (extracted viscose rayon sheets)
- Hilaire de Chardonnet
- Ray P. Dinsmore - pioneered the use of Rayon in tires
References
Further reading
- For a review of all rayon and market production methods see "Cellulose Fiber Regeneration" (book - Edited by C R Woodings) Hardback 2001, ISBNÃ, 1-85573-459-1, Woodhead Publishing Ltd.
- For a description of a production method at a factory in Germany in World War II see AgnÃÆ'¨s Humbert (tr Barbara Mellor) RÃ © union: Memoirs of Occupied France , London, Bloomsbury Publishing PLC, 2008 ISBN 978-0-7475-9597-7 (American Title: Resistance: French War Journal, Bloomsbury, USA, 2008) p. 152-155
- For a complete set of photos from the process see "The Story of Rayon" published by Courtaulds Ltd (1948)
External links
- Definition of Bemberg dictionary in Wiktionary
- Definition of rayon dictionary in Wiktionary
Source of the article : Wikipedia
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