Nutrition Guide

Wood fibres are usually cellulosic elements that are extracted from trees, straw, bamboo, cotton seed, hemp, sugar cane and other sources.

The end paper product (paper, paperboard, tissue, etc.) dictates the species, or species blend, that is best suited to provide the desirable sheet characteristics, and also dictates the required fibre processing (chemical treatment, heat treatment, mechanical ‘brushing’ or refining etc.).

In North America, virgin (non-recycled) wood fibre is primarily extracted from hardwood (deciduous) trees and softwood (coniferous) trees. Wood fibres can also be recycled from used paper materials.

Wood fibres are treated by combining them with other additives. They are then processed into a network of wood fibres, which constitutes the sheet of paper.

Viscose was first used for coating fabrics, a purpose for which it is quite suitable. However, when Cross and his partners tried to make solid objects like umbrella handles they were found to be much too brittle.

Further development led to viscose being spun into thread for embroidery and trimmings. Eventually, after Samuel Courtauld & Co. had taken over in 1904, Viscose manufacture became big business. By the twenties and thirties it had almost completely replaced the traditional cotton and wool for women’s stockings and underwear. Similar changes occurred in the US and in Europe, too. Viscose was also being used for linings and furnishing fabrics; providing the staple for towels and table-cloths and was being made into high tenacity yarn for tires. Yet other uses included the manufacture of sponges and absorbent cloths.

Making viscose film had been tried by Cross in the 1890s but it was in Switzerland and France that major successes were achieved. By 1913 C.T.A. established La Cellophane SA. Ten years later DuPont Cellophane Co. was set up in the USA and in 1935 British Cellophane Ltd was established in Bridgwater, Somerset.

Viscose is a soft material, used in mostly tops, coats and jackets.

Viscose is currently becoming less common because of the polluting effects of carbon disulfide and other by-products of the process, forcing the Bridgwater factory to close in 2005.

Viscose is a viscous organic liquid[1] used to make rayon and cellophane. Cellulose from wood or cotton fibres is treated with sodium hydroxide, then mixed with carbon disulfide to form cellulose xanthate, which is dissolved in more sodium hydroxide. The resulting viscose is extruded into an acid bath either through a slit to make cellophane, or through a spinneret to make rayon. The acid converts the viscose back into cellulose.
Cellulose is treated with alkali and carbon disulfide to yield viscose.

Viscose was created by French scientist and industrialist Hilaire de Chardonnet (1838-1924), inventor of the first artificial textile fiber, artificial silk) in Échirolles in 1891, then the process for manufacturing viscose was patented by three British scientists, Charles Frederick Cross, Edward John Bevan and Clayton Beadle, in 1902.

Supima is a non-profit organisation in the United States whose main objective is to promote the use of American Pima cotton around the world[1] and is involved in quality assurance and research programs. Founded in 1954, it derived its name from superior pima.[2]

Supima licenses over 300 selected high-quality mills, textile and clothing manufacturers, and retailers to use the Supima trademark. Members finance the activities of Supima by payments calculated on a “per bale” basis.

Its other activities include:[1]
research programs to improve the quality of American Pima cotton
timely crop and market information to its grower-members and licensees
advertisements in both consumer and trade publications
presentations to customers both in the USA and abroad
participation in major international exhibitions and events

The Board of Directors of Supima is made up of Pima growers from Arizona, California, New Mexico and Texas.[3]

Production of Supima cotton has risen from about 100,000 bales per year in the 1980s to over 800,000 bales in 2006. More than 90% of Supima cotton is exported from the United States, the majority of this being for the overseas manufacture of finished fabrics, clothing, sheets and towels which are re-exported to the United States for sale. The top five importers of Supima cotton are China, Pakistan, India, Japan and Indonesia.[2]

Trade names are used within the rayon industry to determine the type of rayon used.

Look up Bemberg in
Wiktionary, the free dictionary.

Bemberg, for example, is a trade name for cupramonium rayon developed by J.P. Bemberg that is now only produced in Italy due to United States Environmental Protection Agency regulations in the US [7].

Modal and Tencel are widely used forms of rayon produced by Lenzing Fibers Corp. which is based in northern Austria [8].

Galaxy, Danufil, and Viloft are rayon brands produced by Kelheim Fibres, a German manufacturer. [9]

Acordis is a major manufacturer of cellulose based fibers and yarns. Production facilities can be found throughout Europe, the U.S. and Brazil .[citation needed]

Visil rayon is a flame retardant form of viscose which has silica embedded in the fiber during manufacturing. [10].

North American Rayon Corp of Tennessee produced viscose rayon until its closure in the year 2000. [11].

Grasim of India is the largest producer of rayon in the world (claiming 24% market share). It has plants in Nagda, Kharach and Harihar - all in India.

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 caustic soda: (C6H10O5)n + nNaOH —> (C6H9O4ONa)n + nH2O
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 oxygen
Xanthation: The aged “white crumb” is mixed with carbon disulfide in a process known as 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: (C6H9O4O-SC-SNa)n + nH2O —> (C6H10O5)n + nCS2 + nNaOH
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 acid, resulting in the formation of rayon filaments: (C6H9O4O-SC-SNa)n + ½nH2SO4 —> (C6H10O5)n + nCS2 + ½nNa2SO4
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 [2]

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 mercerized like cotton. HWM rayons are also known as “polynosic” or can be identified by the trade name Modal [6].

High Tenacity rayon is another modified version of viscose that has almost twice the strength of HWM. This type of rayon is typically used for industrial purposes such as tire cord [6].

Cupramonium rayon has properties similar to viscose but during production, the cellulose is combined with copper and ammonia (Schweizer’s reagent). Due to the environmental effects of this production method, cupramonium rayon is no longer produced in the United States [6].

The German chemist Eduard Schweizer discovered that tetraaminecopper dihydroxide could dissolve cellulose. Max Fremery and Johann Urban developed a method to produce carbon fibers for use in light bulbs in 1892. Production of rayon for textiles started in 1899 in the Vereinigte Glanzstofffabriken AG in Oberbruch. Improvement by the J.P. Bemberg AG in 1901 made the artificial silk a product comparable to real silk.

Regular rayon has lengthwise lines called striations and its cross-section is an indented circular shape. The cross-sections of HWM and cupra rayon are rounder. Filament rayon yarns vary from 80 to 980 filaments per yarn and vary in size from 40 to 5000 denier. Staple fibers range from 1.5 to 15 denier and are mechanically or chemically crimped. Rayon fibers are naturally very bright, but the addition of delustering pigments cuts down on this natural brightness [4].

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, cotton and 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 [5].

The durability and appearance retention of regular rayon are low, especially when wet; also, rayon has the lowest elastic recovery of any fiber. However, HWM rayon is 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
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, cotton and 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 [5].

The durability and appearance retention of regular rayon are low, especially when wet; also, rayon has the lowest elastic recovery of any fiber. However, HWM rayon is 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

Finally, in 1894, Charles Frederick Cross, Edward John Bevan, and Clayton Beadle patented their artificial silk, which they named “viscose”, because the reaction product of carbon disulfide and cellulose in basic conditions gave a highly viscous solution of xanthate. Avtex Fibers Incorporated 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-tenacity rayon in the 1940s. Further research and development led to the creation of high-wet-modulus rayon (HWM rayon) in the 1950s [4].