Viscose rayon

viscose rayon fibers, viscose rayon ( Zellwolle) fibers, which are industrially manufactured of the base material cellulose to consist and over the viscose rayon procedure , are short. The chemical nature of the viscose rayon fibers resembles from cotton stapels. Also the typical fiber refinement (about 10 to 15 µm diameters) and Faserlänge (about40 mm) are as a rule similarly that the cotton. For the textile industry the viscose rayon becomes a Endlosfaden versponnen. By the treatment of the cellulose in the viscose rayon procedure - contrary to the natural product cotton - the characteristics of the fiber (color, shining or frosted appearance, Faserlänge can,- thickens and - cross section) to be varied. The viscose rayon is a natural artificial fiber, contrary to the synthetic artificial fibers, as for example polyesters or Polyacryl wide-spread in the present.

Table of contents

use

the use of viscose rayon overlap often with those the cotton (textiles, mix fabrics with polyester uvm.). In range (Nonwovens) have the viscose rayon fiber due to the various organization possibilities larger market shares than within not textilen the textilen range. An example of use is here the employmentin intimate hygiene products (Tampons) due to more favorable liquid photograph characteristics

the chemist Dr. announce historical 1897. Max Fremery and engineer Johann Urban their procedure to manufacture threads out in copper oxide ammonia of solved cellulose to the patent on. This is the birth of the German celanese. Fremery andUrban use their copper oaths first as filaments in their lamp production. For this purpose they created the first production enterprise in upper break (city Heinsberg). To 19. September 1899 is created the united glazed fabric factories AG. Company headquarters is Wuppertal. 1902 closes Fremery and Urban their lamp factory. More importantlyCustomer of the copper oaths becomes now the Besatzerindustrie (e.g. for parachutes). Rapidly they recognize the further potential of the celanese, acquire 1911 the viscose rayon patent and bring it to production-ready ones.

production (viscose rayon procedure)

as raw material for viscose rayon fibers serves cellulose, which from wood of Beeches, spruces, Eukalyptus, Pinien o.a. comes. The necessary wood quantities are usually cultivated and harvested on special farms. The used cellulose quality differs from the paper cellulose quality by the fact that the chain length of the cellulose molecules is higher more briefly and the purity. The cellulose for viscose rayon productionif less remainder contains lignin, less Hemizellulosen /Pentosane, has a better reactivity opposite caustic soda solution and carbon disulfide and a better solubility in caustic soda solution after effected Xanthogenierungsreaktion.

For the production of a spin mass for the Erspinnen of the viscose rayon fibers the cellulose becomes first with caustic soda solution in the classical viscose rayon procedureshifted. In the aqueous caustic soda solution the cellulose pours and forms Natronzellulose. These one lets carbon disulfide (CS 2) affect. Natriumxanthogenat (Xanthat) develops. The orange-yellow Xanthat is solvable in aqueous, diluted NaOH solution and forms therein a viscose rayon (honey-like) for solution. Therefore comes alsothe name of the viscose rayon. This mass with a consistency similarly of warm honey represents the viscose.

Both before the reaction with CS 2 and after the release in caustic soda solution time for the respective chemical reactions is given to the Natronzellulose and/or the spin viscose rayon.To it the Verkürzung of the chain lengths of the polymere cellulose molecules before the Xanthogenierungsreaktion and the relocating reactions belong after the release process. After two or three-way filtration and exhaust possesses then the spin mass the suitable viscosity and the suitable Reifegrad - reactivity opposite the coagulating bath - versponnen become over followingto be able.

Für die Viskosefasern im klassischen Herstellungsprozess wird ein Schwefelsäurespinnbad eingesetzt, welches zusätzlich noch - fast bis zur Sättigungsgrenze - Natriumsulfat und eine geringe Menge Zinksulfat zur Verzögerung der Zellulose-Ausfällungsreaktion enthält. The viscose is pressed by means of gear pumps by the spin nozzles. The typical hole diametera single hole of the spin nozzles about 50 amounts to µm. The sodium Zellulosexanthogenat in the viscose disintegrates in the sour environment of the coagulating bath again into the raw materials cellulose and carbon disulfide (CS 2). The caustic soda solution of the viscose forms sodium sulfate with the sulfuric acid of the coagulating bath. At the same time water develops anddue to secondary reactions a small quantity of evil-smelling, poisonous hydrogen sulfide, which must be removed in a complex gas laundry. Or on simple biological way; by means of the Biotrickling procedure.

The water and the sodium sulfate are removed in the recuperation and reprocessing of the coagulating bath from the used up bath.Sodium sulfate is a ouple product in the classical viscose rayon procedure and to a large extent to the detergent industry is thus sold. The carbon disulfide set free during the spin process is sucked off on the one hand from the spin plants and either recovered directly by absorption at activated charcoal or burned for the purpose of the production of sulfuric acid. Toothers the CS 2 is recovered directly due to its small boiling point of 46 °C by driving out from that freshly gesponnenen fibers by means of steam and following condensation of the vapours and led back into the process. This CS 2 - driving out takes place usually, after the fresh spin cable before stillfor the firmness increase one drew and one cut on the desired Faserlänge. Since the carbon disulfide represents a comparatively expensive raw material, its complete recuperation is aimed at.

For a baumwolleänhliches appearance the viscose rayon fibers during a subsequent treatment process are washed and bleached. Chlorine - free bleaches and the employment of free from chlorine manufacturedCellulose is already in Europe the rule. In order to give to the viscose rayon fibers for the subsequent treatment favorable sliding qualities, before their drying process still Avivagen - soaps - are applied similar substances - in parts per thousand - range on the surface of the fibers.

The viscose rayon fibers (pile fiber) come into bundles with oneWeight of approximately 250 - 350 kg and a fiber residual moisture of approximately 11% on the market. Viscose rayon threads are rolled up with Spulengewichten by approximately 1.5 - 6.0 kg. Here usually titers between 40 and 660 become dtex gesponnen.

production companies

the largest manufacturers world-widethe companies are Lenzing AG in Austria and Birla Rayon in India. Lenzing the world largest manufacturer of zellulosischen fibers, that is simultaneous is viscose rayon fibers, Modalfasern and Tencel /Lyocellfasern collected. The largest individual production roads stand at the company South Pacific Viscose in Purwakarta/Indonesia alsoa daily performance of nearly in each case 150 tons. The largest European producer of textilen viscose rayon filament yarns is the Enka GmbH & CO kg in Wuppertal.

related products

a similar product as viscose rayon fibers are Modalfasern. They consist likewise to 100% of cellulose and become,as viscose rayon fibers, made of natural cellulose. By a somewhat different process one reaches higher fiber strengtheningnesses and improved fiber characteristics with the Modalfasern. Likewise into the class of the zellulosischen fibers the Tencel and Lyocellfasern are to be arranged. These are manufactured with the same basic process. After the purchasethe mark Tencel of the Austrian Lenzing AG (Lyocell) the mark name Tencel of Lenzing was taken over, because this has a higher admitting heating degree than the mark Lyocell. With Tencel /Lyocellfasern the cellulose becomes by the innocuous solvent NMMO (N-Methylmorpholin-N-oxide) without previous reaction with caustic soda solution and Derivatisierungto the Xanthogenat directly and invariably dissolved. Spiders Tencel /Lyocellfasern takes place in a diluted, aqueous NMMO bath, whereby the solubility border of the cellulose is fallen below and thus a thread is formed.

As viscose rayon fibers the designation “synthetic artificial fibers” or “Synthetikfasern” is unfounded also with Modal and with Tencel /Lyocellfasern.The raw material for these fibers is cellulose, which is made of wood by the distance of the binding materials (lignins) directly and without chemical action. The conversion of the cellulose to the Zellulosexanthogenat in the classical viscose rayon fiber process serves only for the achievement a solubility and ends finally after that to spiders againin the raw material cellulose. Compared with genuine Synthetikfasern, which are made of raw materials on basis by oil or natural gas, viscose rayon fibers contribute substantially less to the increase of the CO 2 - content in the atmosphere and thus to the greenhouse effect. Those is more applicable for viscose rayon, Modal and Tencel /LyocellfasernDesignation “orientation by nature fibers” or “natural artificial fibers”.

Web on the left of

pdf over “cellulose and Polyosen as chemistry raw materials”

Website of the Enka AG of world largest viscose rayon manufacturers

Website of the Kelheim Fibres GmbH

Website of the Lenzing AG

Website of the South Pacific Viscose/Indonesia

didactics of chemistry to the FU Berlin: Viscose rayon procedure

 

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