Viscose silk

Carbon disulphide is an excellent solvent for fats, oils, rubber, sulphur, bromine and iodine, and is used industrially as a solvent for extraction. It is also used in the production of viscose silk, when added to wood cellulose impregnated with sodium hydroxide solution, a viscous solution of cellulose xanthate is formed, and this can be extruded through a fine nozzle into acid, which decomposes the xanthate to give a glossy thread of cellulose. 

Calcium bisulphite is largely used in the manufacture of sulphite pulp, from which paper and viscose silk (see p. 264) may be produced. Wood chips or shavings are boiled with the bisulphite under pressure and so yield cellulose, which at the same time is bleached. The bisulphites of magnesium and the alkali metals are also sometimes used. 

Uses and Physiological Properties of Carbon Disulphide.—Besides its employment as a solvent (see p. 260), carbon disulphide is used extensively in the manufacture of viscose silk. Viscose is a solution of the sodium salt of the cellulose ester of thiolthioncarbonic acid (p. 268) in water or dilute aqueous sodium hydroxide, or it may be described as an aqueous solution of the sodium salt of cellulose xanthic acid. For its production cellulose is steeped in concentrated sodium hydroxide solution and then pressed, the product being called alkali-cellulose and the formula CeH10O5.NaOH assigned to it. This is converted into viscose by treatment with carbon disulphide, when the colour changes to golden yellow ... 

This product, after keeping for four or five days, is pressed through a rose perforated with small holes into a coagulating bath containing, for example, aqueous sulphuric acid (10 per cent.), when hydrated cellulose is precipitated in solid threads, which after purification and washing constitute viscose silk. 

A. Mixed fabric containing cotton, wool, natural silk and artificial cellulose, nitrocellulose or viscose silk. 

Technical Observations. Tetrazotized benzidinedicarboxylic acid gives, with 2 moles of l,8-aminonaphthol-2,4-disulfonic acid (Chicago acid, see page 217), a disazo dye which, in tlie form of its copper compound on viscose silk, gives a bright blue shade having extraordinary light fastness. 

Viscose Silk.—III. From Cellulose Xanthate. We have referred to the solvent action of xanthic acid, which is the ethyl ether of di-thio-carbonic acid, viz., HS-CS-OC2H5. When sodium cellulose is dissolved in xanthic acid the cellulose is in the form of sodium cellulose xanthate. A solution properly prepared by treating cellulose with sodimn hydroxide and carbon di-sulphide in the presence of benzene or carbon tetra-chloride, in which polymerization of the cellulose compound is effected, is decomposed by forcing capillary streams of the solution into a solution of ammonium sulphate. The cellulose is thus obtained as in the other processes in the form of fine filaments of a hydrated cellulose possessing silk-like properties. Artificial silk of this type is known as viscose silk and is made in large quantities. In 1914 about 20,000,000 pounds of artificial silk were made, of which about 3,000,000 pounds were made in the United States. Most of this product was viscose silk. 

Adverse ocular effects in workers of a viscose silk plant exposed 6 hours a day, 5 days a week, for 0.5-30 years to less than 3.2 ppm carbon disulfide were reported by Szymankova (1968). Disturbances were manifested as vascular or inflammatory degenerative changes in the retinas of 12 out of 75 (16%) of the exposed workers, which disappeared in 11 workers following cessation of carbon disulfide exposure. 

USE Manuf ammonia alum in the manuf of HjS04 to free it from nitrogen oxides analytical uses freezing mixtures, flameproofing fabrics and paper manuf viscose silk tanning, galvanizing iron in fractionation of proteins. The commercial grade is used as fertilizer. 

The dichroism in natural fibers with incorporated metal nanoparficles was found to depend strongly not oidy on the element employed [50] but also on the particle size [51], which was calculated from the full-width at half-maximum of X-ray diffraction patterns, yielding values between 5 and 14 nm in ramie, hemp, bamboo, silk, viscose silk, acetate rayon, and wool fibers [51]. As an example of a particle-size-dependent dichroism, a color transition between perpendicular and parallel orientation of polarization plane and long fiber axis in ramie fibers appeared from straw yellow to indigo blue for gold particles of 8.5-nm diameter and from claret red to green at 12.3-nm diameter [51]. 

The name rayon was officially adopted in 1924 by the National Retail Dry Goods Association. Prior to this, the fiber was called artificial silk, wood-silk, or viscose silk. On October 26, 1937, the Federal Trade Commission (FTC) officially defined rayon as a textile fiber or yarn produced chemically from cellulose or with a cellulose base. This definition covered cuprammonium and viscose rayon as well as acetate fiber. To avoid confusion in the trade, FTC rules were adopted on December 11, 1951, which defined rayon as man-made textile fibers and filaments composed of regenerated cellulose. A separate definition was adopted for acetate, man-made textile fibers and filaments composed of cellulose acetate. ... 

Classification Thioindigoid color Empirical C18H10CI2O2S2 Properties Bluish pink m.w. 393.30 Toxicology Mutagen TSCA listed Uses Dye for cotton, viscose, silk, wool colorant in cosmetics, hair dyes, pharmaceutical orals Regulatory D C Red No. 30 FDA 21CFR 74.1330, 74.2330, 82.1330 FDA approved for orals... 

Regenerated fibers are fibers produced from material of natural origin. The material undergoes some chemical process or modification (viscose silk, acetate silk, nitrocellulose, alginate fibers, etc.). Synthesized fibers are synthetic fibers completely synthesized from other raw materials. 

To produce viscose silk (rayon), the next stage is spinning under 3-5 bar pressure into what is known as a Muller bath, which consists of 7-12% H2SO4, 16-23% Na2S04, and 1-6% Zn-Mg-NH4-sulfate. Here, two events occur simultaneously coagulation of the cellulose xanthate and hydrolytic decomposition to cellulose with the reformation of CS2. As by-products, H2S and COS are found in the exhaust air and elementary sulfur (as sodium polysulfides) in the bath and on the fibers. Sodium sulfate should decrease dissociation and thus lessen the osmotic pressure drop of the bath with its high electrolyte content relative to the fiber gel, which is low in electrolytes. 

Viskoseseide/Viskoserayon viscose silk, viscose rayon... 

Ubbelohde-Viskosimeter viscometric flow viskometrische StrOmung viscose fiber ViskoseFaser (CV) viscose process (xanthate process) ViskoseverFahren viscose silk/ viscose rayon/rayon Viskoseseide,... 

Absorbent pads, Cotton, viscose, silk, polyamide. Nonwoven, knitted, woven... 

Silk Nylon Cotton Viscose Silk Nylon... 

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