The goal of our Know Your Fibers series is to provide info about different types of fibers for our readers. This quarter, we take a look at Tencel ®.
A Brief History of Tencel ®
Lyocell is a form of rayon which consists of cellulose fiber made from wood pulp. It was first developed through the pilot stage by (the now-defunct) American Enka in 1972, and they called it Newcell. Later, the fiber was commercialized by Courtaulds Fibers in the 1980s. In 1990 the first plant was opened in Mobile, AL, and Courtaulds renamed the fiber “Tencel.” When Lenzing AG purchased the Tencel plants in 2004, they combined it with their lyocell business, but they kept the Tencel® name. They are the only major producer of lyocell fiber.
The Federal Trade Commission assigned the separate generic name of “lyocell” and classifies it as a sub-category under rayon. Tencel® fibers (which is now the Lenzing brand name) are lyocell fibers and therefore a sub-category of rayon. Lenzing is using the Tencel® branding on packaging of consumer products, which consists of both nonwovens and woven/knit fabrics.
Rayon vs. Lyocell Process
As mentioned earlier, the raw material for lyocell (Tencel®) is wood pulp, and like rayon the pulp is milled and bleached. The cellulose after this process is dissolved in an organic solution and extruded through a spinneret which has small holes (the diameter of the holes determines the fiber diameter). On the other side of the spinneret, the organic solvent is removed and forms fiber filaments, one per hole. These filaments are cut into the desired fiber lengths and baled to be sold. This process allows for the recycling of almost all the organic solvent for reuse. Rayon does not allow for recycling so there are waste streams associated with its manufacturing.
Tencel ® Properties
The main difference in Tencel® fiber versus rayon is it has higher tensile strength, both wet and dry. Tencel® does lose some strength when wet, though not as much as rayon (of course, purified cotton is stronger when wet). The degree of polymerization is great in Tencel®; it’s about twice that of rayon, but cotton is still four to six times higher—which is why cotton does not lose strength when wet.
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