Solvent spinning lyocell

Lyocell is the first in a new generation of cellulosic fibres made by a solvent spinning process. A major driving force to its development was the demand for a process that was environmentally responsible and utilised renewable resources as their raw materials. The first samples were produced in 1984 and commercial production started in 1988. A wide range of attractive textile fabrics can be made from lyocell that are comfortable to wear and have good physical performance. This physical performance combined with its absorbency also make lyocell ideal for nonwoven fabrics and papers. 

The production of lyocell is a new technology for producing cellulosic fibers by means of a direct solvent process. This means that a genuine solution of the cellulose in N-methylmorpholine-N-oxide (NMMO) monohydrate is produced and spun, and not a cellulose derivate as in the case of viscose. The cellulose can, however, be obtained from used textiles or by crushed wood pulp. After filtration of the honey-like spinning solution, it is spun through an air gap into diluted aqueous NMMO solution. 

In contrast to conventional cellulosic chemical fibers, lyocell fibers are manufactured without production of a cellulose derivate in either the dissolution or the actual spinning of the cellulose. The name lyocell fibers comprises all fibers that are solvent-spun cellulosics. By definition, an organic solvent applied in the sol-vent-spinning production process consists of a mix of chemicals in water. 

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