Nonwovens from hydrophobic Lenzing Lyocell Dry fibers (Source: Lenzing)
The EU Single-Use Plastics Directive (SUPD) has already led to major changes and challenges in the nonwovens market. Product compositions that have been proven over many years in terms of their performance must be questioned, as they now no longer meet the required sustainability criteria. In fact, plastic-based fibers are not only characterized by diversity and some positive properties, they are also of fossil origin and non-biodegradable. This ultimately contributes to large amounts of plastic waste being found in our environment worldwide, especially in our oceans. The amount is equivalent to one truck load/minute or 12 million tons/year. Approx. 8 % of this waste can be attributed to the nonwovens industry. A diaper made of plastic materials can take up to 450 years to disappear from the environment.
Since both industry and consumers are less and less willing to accept the labels on packaging that have become necessary due to the SUPD, alternatives are now in demand.
Cellulosic fibers such as Lenzing Viscose fibers or Lenzing Lyocell fibers can provide these alternatives. The SUPD clearly states that these fibers are natural polymers (cellulose) and are therefore not considered plastic. Their origin is in the forest, where cellulose is synthesized by trees. However, since not every substance of natural origin is also easily biodegradable, this was tested for cellulose fibers from Lenzing AG by the renowned Scripps Research Institute, San Diego, CA/USA, not only under laboratory conditions, but especially elaborately also directly in the sea.
The result showed that while synthetic fibers made of polyester (PET), polypropylene (PP), but also bio-based polylactic acid (PLA) fibers, showed almost no degradation during the entire measurement period, the Lenzing fiber samples were already completely degraded well below the time allowed for achieving the “OK biodegradable marine” label.
Biodegradation of nonwovens samples made of different fiber materials in the sea. After only 14 days, the cellulosic fibers are almost completely degraded, while the nonwovens made of synthetic polymers and PLA show hardly any degradation even after 77 days. (Source: Lenzing)
Corresponding tests for fresh water show the same behavior, but also under all other relevant environmental conditions, e.g. home compost, the degradability of the fibers is very good.
This means that products made from these fibers do not cause any problems even if they are unintentionally released into the environment. Nature can handle the natural material cellulose very well.
However, apart from its easy biodegradability, fiber material made of cellulose has other advantages, brings valuable properties with it, and thus allows many customized solutions. Cellulose is hydrophilic by nature and can therefore absorb moisture. This is a property that, together with the vapor permeability that is also provided, is very important, e.g. in terms of comfort and well-being when such materials are worn close to the skin.
The microporous character of the material additionally increases its ability to absorb liquids and can be used for many different purposes.
Their versatility is also demonstrated by a variety of other adjustable properties such as mechanical parameters, cross-sections, etc. Ultimately, cellulose is chemically distinguished from other polymers by the OH groups on its surface, which easily allow all kinds of further modifications.
The property profile covered by cellulosic fibers as a result of all this makes them the ideal material for all nonwovens applications such as hygiene products or wipes. They also lead to unique product advantages in the textile segment and for a wide range of technical applications. The resulting application and product possibilities are almost limitless.
The SUPD is one part of the European Union (EU) action plan for circularity. With Eco Cycle technology for nonwovens fibers or the Refibra technology for textile fibers, Lenzing contributes to this action plan. These technologies use cotton residues from recycled cotton textiles that would otherwise be incinerated or landfilled. They are mixed with pulp and used as feedstock for Lenzing Lyocell fibers, creating fibers with the same properties as lyocell fibers from virgin material. This is not only possible in the laboratory, Lenzing also offers this material on an industrial scale. This approach fits well with textile recycling under the EU Green Deal.
For some applications, however, the natural advantages of cellulose are not sufficient, and one has to get closer to the properties of synthetic fibers, e.g. regarding hydrophobicity.
Hydrophobic Lenzing Lyocell Dry fibers (source: Lenzing)
Lenzing does this with the Dry Technology and the Lenzing Lyocell Dry fibers. This technology turns hydrophilic cellulose into hydrophobic high-performance fibers that have a water contact angle of approx. 120°, while of course still being bio-based and biodegradable. This makes Lenzing Lyocell Dry fibers a very good and sustainable alternative to synthetic fibers, for example for top sheets in absorbent hygiene products.
Cellulosic fibers thus already represent a real alternative to synthetic fibers in many applications, especially for single use articles covered by the SUPD. The unique properties of cellulose as a raw material offer solutions to almost all of today's problems and will continue to do so for future challenges.