Viscose (artificial silk)

Viscose fibers (international abbreviation: CV) are products made from regenerated cellulose. Cellulose, as the basic raw material for viscose production, is a natural polymer, an organic compound with a molecular chain. 

In 1855, Swiss inventor Audemars discovered nitrocellulose, from which Hilaire de Chardonnet first produced a textile fiber in 1884. He received a French patent for the technology and began industrial production of the fiber. In the 20th century, several types of modified viscose fibers were developed, such as polynosic from Japan, high wet modulus (HWM) fiber, or Tencel fiber (solvent spinning). The consumption of viscose fibers was first recorded worldwide in 1930 at about 240,000 tons, estimated at 2 million tons in 1960, and 4 million tons in 1973. In 2017, consumption reached 6 million tons, with about 30 companies involved in their production. One of the largest is the Austrian company Lenzing AG (17% share), which also includes a plant in Paskov in the Moravian-Silesian region (258,000 tons of cellulose).

The raw material for the production of viscose fiber is cellulose made using the sulfate process from beech wood (in Europe) or spruce and eucalyptus wood (in Asia). From cellulose, a xanthate is formed by dissolving in sodium hydroxide, from which a continuous textile fiber is produced after passing through a jet in a bath of sulfuric acid and zinc sulfate. The fiber is then refined by stretching, chemically treated, and possibly cut to length according to the conditions of further use. In addition to the basic type of fiber, modified types are produced (usually with the help of chemical treatment of the spinning bath), for example, lyocell, high-strength, polynosic, flame-retardant fibers (FR), etc. About 3 tons of wood are consumed per ton of viscose fibers. Fibers are produced in finenesses from 0.9 to 28 dtex, filaments from 6.7 tex f18 up to 200 tex f700. The majority of fibers are cut to lengths of 20-60 (mainly for processing into cotton yarns), at the beginning of the 21st century, about 10% were processed into nonwoven textiles, and 15% of fibers were produced in filament form.

Viscose fibers of all types have a specific gravity of 1.52 cN/cm3 and high moisture absorption (26-28%). Standard fibers have low strength and high elongation when wet, they shrink at higher temperatures, and are flammable. They are easy to dye and bleach, after washing they have a low tendency to fray and pill. The average price of viscose fibers reached about 2 USD/kg in the 2nd decade of the 21st century.

Staple yarns from viscose staple fibers are mainly produced from blends with natural and synthetic fibers in finenesses of about 10 tex. Fabrics and knits made from them are used for outerwear, underwear, home and decorative textiles, and hand-knitting yarns. Filament yarns are processed by weaving (about 80%) or knitting, mainly used for lining and tire cords. Nonwoven textiles from viscose fibers are best known for medical supplies.