When one thinks of man-made fibres, one often thinks of the most diverse synthetic polymers. However, regenerated fibres are a subgroup of man-made fibres. These are based on naturally occurring renewable raw materials that are processed into fibres in chemical manufacturing processes. For this reason, these fabrics are often described as semi-synthetic: half natural, half artificial.
Most people now know that paper is made from wood. However, it is less well known that wood is also the raw material for textiles. With the help of chemicals, it can be broken down into its individual components to obtain the cellulose needed exclusively for the production of textile fibres and clothing materials.
Viscose - regenerated fibre from wood
The classic textile fibre made from the cellulose of wood is viscose. The process for viscose production has been known since the early 20th century. It is based on complex chemical processes, whereby the comminution of the wood is followed by cooking and bleaching processes, dissolving and spinning processes. The cellulose is dissolved and then pressed through spinning nozzles. Solvents and chemicals are therefore absolutely necessary for the spinning process, which explains why viscose does not belong to the natural fibres but to the large group of man-made fibres. A misleading classification, because ultimately the chemicals are only part of the production process and not part of the fibre itself. In the end, the fibre is freed from all chemicals and consists of 100 percent cellulose, the main substance of wood.
Lyocell - the environmentally friendly alternative
The viscose manufacturing process has been continuously developed, resulting in the creation of the modal fibre, for example. It is a special viscose fibre that is stronger and more durable due to an improved process. The real innovation, however, came from the Austrian company Lenzing with Lyocell® - a new generation of fibres that are produced in a much more environmentally friendly way. This method is essentially based on dissolving cellulose in the organic and non-toxic medium NMMO (N-methylmorpholine-N-oxide) and producing fibres from this solution. In contrast to normal viscose production, no caustic soda is used here and only non-toxic solvents are used.
The special thing about this is that Lenzing found a way to keep the solvents used in a closed cycle and to recover 99.8 percent.
Let's take a closer look at a Lyocell fibre from Lenzing: Like many other new fabrics, Tencel® is a protected trademark. Depending on how it is processed, Tencel resembles silk, suede, moleskin or wool. Since Tencel is made from a vegetable raw material (mostly eucalyptus), the fabric is biodegradable. The chemicals used during production are collected and reused according to the closed-loop principle.
Also good: eucalyptus can be grown in Europe, which saves considerable emissions during transport. In addition, eucalyptus is considered extremely high-yielding and therefore requires a small area for cultivation.
Cotton – potentials already exhausted
Currently, cellulose fibres made from wood account for 6 per cent of total global fibre production. It is very likely that there will be an increased demand for wood-based textiles in the coming years.
The reason for this should be the steadily increasing demand for clothing, driven by the rising world population and the fact that fashion cycles have become shorter. The increased demand cannot be met by cotton, as indicated by the declining share of the fibre market: in 1990, cotton accounted for 49 per cent of the market, in 2000 it was only around 40 per cent and today it is 33 per cent.
The main reason is that the cultivation of cotton requires large amounts of land and water - resources that are only available in limited quantities and are urgently needed primarily for food production.
Sustainable fashion from wood fibres
High-quality natural products are produced from the renewable raw material wood with the help of closed chemical cycles as well as energetic optimisation. We talk about energetic optimisation because everything left over from the tree trunk is used to generate energy and thus 87 percent of the energy required for the manufacturing process is generated by burning the bark.
Compared to the fully synthetic materials, the regenerated fibres score with excellent material properties: Wood-based fibres absorb moisture, whereas with synthetic materials such as polyester, moisture absorption is impossible due to the structure. Cellulose fibres are able to absorb water through the pore structure, store it and release it when needed. This leads to active moisture and thermoregulation, neutral electrical as well as antibacterial properties.
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