Lyocell

from Wikipedia, the free encyclopedia

Lyocell ( CLY ) is from cellulose existing, industrially produced cellulose regenerated , which is produced by the direct-solvent procedure. It is mainly used in the textile industry , but also for nonwovens and technical applications. Lyocell is the generic fiber name and is offered by Lenzing AG under the brand names TENCEL ™ and TENCEL ™ × REFIBRA ™ .

properties

Lyocell fibers have high dry and wet strength, are soft and absorb moisture very well. Produced therefrom textiles have a smooth and cool touch, drape, have a low tendency to wrinkle and can be washed and dry cleaned.

Lyocell fibers are available in a wide range of microfibres with 0.9 dtex (0.9 g per 10,000 m thread length) to coarse fibers with 15 dtex. Due to its fibrillation, standard lyocell can be used for textiles with a peach-like, velvety surface (peach-skin effect) or it can be stabilized in the textile with a suitable finish . Non-fibrillating Lyocell fibers are produced for other applications.

Manufacturing

The cellulose is extracted from the raw material wood. The thus obtained pulp is comminuted and then treated with N -Methylmorpholin- N oxide (which is but eye and skin irritant and can cause irritation of the respiratory system) (NMNO), a non-toxic solvent, and water are mixed in a stirred tank. Some of the water is removed from the pulp in a stirred tank under vacuum and at elevated temperature . As soon as the water content has dropped to a certain value, the cellulose dissolves and forms a spinning solution that is filtered and then pressed through spinnerets. The filaments formed in this way are precipitated in a bath with an aqueous NMMO solution and combined as fiber cables. Depending on the application, further treatment steps follow such as cleaning, finishing and drying, crimping and cutting. Compared to other regenerated cellulose fibers such as viscose , the manufacturing process is considered to be significantly less polluting due to the environmentally friendly solvent and a closed material cycle, but occupational safety aspects must be observed.

use

The fiber is used in many areas, for example for the production of denim , blouse fabrics, underwear, functional textiles in sports, for work clothing, bed linen and blankets and as a nonwoven product (nonwoven fabric) for hygiene and cosmetic articles. The fiber is also used in textiles in the medical field and for industrial products. They are often used in a mixture with different fibers such as cotton or viscose (modal) and also with synthetic fibers such as polyester and polyamide .

Biodegradation

Lyocell is a modified cellulose fiber and accordingly biodegradable by microorganisms . According to Lenzing, biodegradation in the soil, in compost and also in seawater has been tested in accordance with the applicable guidelines EN 14046 (2003) and ISO 14855 (2005) and certified by a Vinçotte seal. On the basis of disintegration experiments, a weight loss and thus a biological degradation of Lyocell fabrics of around 75% within 60 days could be demonstrated, which means that the biological degradation took place faster than with the biodegradable plastics PHBV , PBS and PLA as well as various composites made from them Materials with lyocell fibers. Lenzing itself states a disintegration time of 100% in 16 weeks.

history

The viscose fiber manufacturers and competitors Lenzing AG and Courtaulds plc have been producing Lyocell fibers since the 1990s, including on the basis of licenses from the Dutch Akzo . In 1987 Courtaulds plc in Grimsby (UK) commissioned the first semi-commercial lyocell plant. In 1990 Lenzing AG started with a pilot plant. Lyocell fibers have been produced commercially since 1991 by Courtaulds in Mobile, Alabama (USA) under the name Tencel and since 1997 by Lenzing in Heiligenkreuz (Austria). After several changes of ownership of the former Courtaulds Group, the Tencel division was spun off.

In 2004 Lenzing took over the Tencel group. After the takeover, Tencel operated one plant each in the United States (Mobile, Alabama), one in Great Britain (Grimsby) and one in Austria (Heiligenkreuz) as well as a pilot and research plant at the Lenzing site . The total nominal capacity in 2016 was around 200,000 tons per year. In 2014, Lenzing AG took over the world's largest Tencel production facility at the Lenzing site with an annual capacity of approx. 67,000 tons in operation. A planned facility in Mobile, Alabama, which was scheduled to go into operation in 2018, has been stopped for the time being due to the uncertain customs situation in the USA. A Tencel plant with a capacity of 100,000 tons per year is scheduled to go into operation near Bangkok in 2021. It should be the world's largest plant of this type.

Web links

Individual evidence

  1. ↑ Database of the European Chemicals Agency ECHA | https://echa.europa.eu/de/brief-profile/-/briefprofile/100.028.538
  2. ↑ Production process of Tencel and Lenzing Lyocell ( Memento from May 25, 2010 in the Internet Archive )
  3. ↑ Greenpeace magazine, 2009: textile primer 3, pp. 49–51.
  4. ↑ a b Wolfgang Plasser, Shayda Rahbaran: Biodegradability of wood-based cellulose fibers. Presentation at the event World of Wipes 2017 , 12. – 15. June 2017; accessed on July 2, 2018.
  5. ↑ Mitsuhiro Shibata, Shingo Oyamada, Shin-ichi Kobayashi, Daisuke Yaginuma: Mechanical properties and biodegradability of green composites based on biodegradable polyesters and lyocell fabric. Journal of Applied Polymer Science 92 (6), June 15, 2004; Pp. 3857-3863. doi : 10.1002 / app.20405 .
  6. ↑ Factsheet. Retrieved June 28, 2017 .
  7. ↑ Lenzing AG takes over Tencel Group. ( Memento of the original from January 28, 2015 in the Internet Archive ) Info: The archive link was inserted automatically and has not yet been checked. Please check the original and archive link according to the instructions and then remove this notice. Lenzing AG press release of May 4, 2004, accessed on June 2, 2009. @1@ 2Template: Webachiv / IABot / www.lenzing.com
  8. ^ Lenzing Group: Locations , accessed on June 14, 2009.
  9. ^ [1] Lenzing press release of October 9, 2015.
  10. ↑ Lenzing stops 275 million project in USA - share collapses in the press on September 27, 2018, accessed on June 26, 2019.
  11. ↑ Lenzing is building the world's largest lyocell plant in Thailand in the OÖ Nachrichten of June 26, 2019, accessed on June 26, 2019.