The lyocell, An Environmentally Sustainable Fiber
The continuous search for better, sustainable and environmentally friendly fabrics has led to some interesting inventions. One of such creations is the Lyocell fabric commonly known as Tencel.
Lyocell is a natural, manmade material made from wood cellulose or pulp. This is done using an advanced solvent spinning process. It was first developed at the now-defunct American Enka fibers facility in 1972. Then it was further developed and marketed in the United States as Tencel hence, its name by Courtaulds. Later on, the Tencel division was sold to Austrian company Lenzing AG, a textile giant and a major lyocell producer in the world.
The versatility of lyocell fabric is evident in the many different things it’s used for. It is used to make things like bed linens, denim, shirts, T-shirts, trousers, and even towels.
A fiber made of cellulose
There is some discrepancy as to which category lyocell falls under. To understand this let’s look at it this way; You see many people who are not familiar with the different types of fabric presume that there are two principal categories of fibers: natural fibers like wool, hemp, cotton, ramie and silk; and artificial fibers synthesized out of petrochemicals like polyester and nylon.
Lyocell falls somewhere in-between. The main raw material for lyocell is the cellulose from wood pulp (gotten from trees like Eucalyptus, Oak, and Birch) which is chemically broken down in a soupy sludge which is then pumped out through a showerhead spinneret and reformed into more easily woven fibers. Thus, Lyocell can be accurately referred to as a recovered or regenerated fiber.
How is Lyocell made?
Making the pulp. Trees such as Eucalyptus, Oak and Birch are harvested from tree farms or forests and sent to the mill to be debarked and chopped into several pieces. These wood pieces are then put into chemical digesters to soften them into a wet pulp. Later the pulp is washed with water and in some instances bleached. It is dried and then rolled up onto spools.
Dissolving the cellulose. The next step is to dissolve the cellulose by breaking it into small pieces and loading it into heated, pressurized containers filled with amine oxide.
Filtering. At this stage as soon as the cellulose in the solvent dissolves into a clear solution, it is squirted out through a filter, to make sure that all the chipped cellulose was dissolved.
Spinning. At this stage, the solution is pumped through spinnerets. Spinneret looks like a showerhead, so when the cellulose is forced through it, long fiber strands come out. This will set the fiber strands and later washed with de-mineralized water.
Dry and lubricate at this stage water in the lyocell fiber is removed by heating it. At this point, the fiber strands pass through a finishing area, where a lubricant like soap, silicone or some other agent is applied. This helps to untangle the fiber strands and facilitate the process of carding and spinning into yarns.
Carding. At this level, the tow (that is the dried and finished fiber strands are called tow which is basically a large bundle of untwisted filaments) is compressed by a crimping machine to give it texture and bulk. Then a machine cards (combs) the fiber. That is it separates the fiber strands. And lastly, the carded fiber strands are rolled up and sent or shipped to a fabric mill.
So the major production steps are summarized as follows:
- Using amine oxide to create a solvent solution from cellulose
- Spinning lyocell fiber from the amine oxide solvent solution
- Washing the lyocell fiber to remove solvents
- Dyeing the fiber and producing yarns
- Finishing to produce lyocell fabric
Why Lyocell is environmentally-friendly
- Lyocell fabrics are naturally biodegradable.
- The production of lyocell produces no harmful byproducts
- The main ingredient, cellulose, is easily gotten from managed tree farms.
- The amine oxide solvent is non-toxic.
- The farming of trees to produce lyocell materials does not require irrigation or pesticides.
- The amine oxide is recyclable. That is after using it to break down the cellulose spin and setting, the amine oxide can be re-used in the manufacturing process again.
- When compared to the manufacture of other cellulose fibers, lyocell production is significantly less toxic and wasteful.
- The amine oxide solvent used is non-toxic, and because most of it is recycled during production, it is not released into the environment.
- Production of lyocell is short. It takes about two and a half hour from chopping the wood down to the carding. Thus, compared to the production of other manmade fibers it uses less water and energy.
Theses properties of the lyocell material have made it a star in the realm of fashion and textile industry.
Advantages of using lyocell fabric
Lyocell fibers are smooth, elastic and are very resistant to wrinkles.
Lyocell is said to be anti-bacterial because of its moisture management property.
Lyocell material has a very smooth, soft surface that drapes beautifully. In terms of the way it feels it is soft, breathable, lightweight and comfortable.
This fabric has greater moisture absorption than cotton and natural breathability. This makes Lyocell fabric a perfect choice for people with sweating issues, or for people with sensitive skin aggravated by moisture.
Appropriate for sensitive skin
The wicking abilities of Lyocell materials keep the skin dry and the smooth fiber surface feels soft and supple against the skin. This makes lyocell fabrics great for sensitive skin.
Lyocell fabric has controllable fibrillation (the very fine fibrils or hairs found on the external surface of fiber strands) this means it can be arranged in various ways from a silky smooth finish to a suede-like softness.
Disadvantages of the lyocell fabric
From a consumer’s perspective, lyocell fabric is more expensive. This is because of the technology used in processing. It simply costs more to produce, and this is transferred to buyers.
Fairly low surface energy
The fairly low surface energy of Lyocell fiber makes it difficult for dyes to bind to it during production.
That said we cannot talk about lyocell and not compare it to the mainstream material which is cotton. For the most part, cotton is still thought of as the gold standard when it comes to fabrics this is mainly because of the price. Cotton fabric is way cheaper to buy compared to lyocell fabric.
How to wash lyocell fabric?
Whether you are buying lyocell fabric/Tencel to sew your own clothes or perhaps you buy clothes made of Tencel, learning how to keep them clean can help you maintain their fine texture.
Garments like bed linens, tops, trousers, scarves, that are 100% made up of lyocell fabrics should be hand washed in a container of warm or cool water and with a mild detergent. Hand washing is gentler and is enough to prevent damage. Remember never to twist or squeeze the wet fabric and air dry it using a hanger. Moreover, undesired stiffness can be removed by putting the garment with a towel into a dryer on low setting to improve the garments softness.
Some garment manufacturers combine lyocell fabric with other materials like cotton or nylon to reduce cost. Washing this type of garment is tricky. So make sure you read the label on the garment first. If it says you should dry clean then dry clean it.
However, for treated lyocell fabrics you can use a washing machine and dryer. Just make sure it’s on the low or medium setting.
Note: garments that are 100% lyocell fabric do not use a washing machine or a tumble dryer. Fully wet lyocell fibers lose almost half of their tensile strength and can tear.
It is advisable to use oxygen-based bleach to whiten and remove stains on lyocell fabrics although some can take diluted chlorine bleach. See the garment label first.
How to iron lyocell ?
Use the lowest iron temperature setting that will produce steam (medium setting max)
Always iron on the wrong side of the fabric.
Use a pressing cloth between the lyocell fabric and the iron.
Note: ironing at very high temperatures can scorch cellulosic fibers.