Who’s the Fairest of Them All?
We've broken down popular bedding materials to determine, who is the fairest of them all. Firstly, all three of these fibers are called “cellulosic fibers” since the natural material that makes up the fiber is cellulose, a component of all plants.
Three Generations of Technology
Rayon was the first generation of these cellulosic fibers. It is known by the names viscose rayon and art silk (abbreviated from “artificial silk”) in the textile industry. It has a high lustre quality giving it a bright shine. Modal is the second generation and is known for its softness and lyocell is now third generation technology.
Unlike other man-made fibers, rayon, modal, and lyocell are not synthetic. They are made from cellulose, commonly derived from wood pulp, and more recently from bamboo. They are neither a truly synthetic fiber (in the sense of synthetics coming from petroleum) nor natural fibers (in the sense of processing fibers that are produced directly from plants or animals, such as wool).
However, their properties and characteristics are more similar to those of natural cellulosic fibers, such as cotton, flax (linen), hemp and jute, than those of thermoplastic, petroleum-based synthetic materials such as nylon and polyester.
Let’s Take Them In Sequence Starting With Rayon
Rayon is the first generation of these fibers and the one that further enhancements were built upon. There are many different processes for manufacturing rayon that vary between the chemicals used and their subsequent impact on the environment.
The production of rayon also applies to modal and lyocell: purified cellulose, often from trees, is converted into a soluble compound. A solution of this compound is passed through a spinneret (similar to the holes in a showerhead) to form soft filaments that are then converted or “regenerated” into almost pure cellulose in the final product.
Rayon fabrics can have different strength and stretch characteristics created by adjusting the drawing process applied in spinning. Regular rayon has the largest market share and is typically found in apparel and home furnishings, it is identified on labels as “rayon” or "viscose.” The distinguishing property of regular rayon is its low-wet-strength.
Rayon's cellulosic base contributes many properties similar to those of cotton or other natural cellulosic fibers. Rayon is more moisture absorbent than cotton, soft, comfortable to wear, drapes well, and is easily dyed in a wide range of colours. It does not build up static electricity, nor will it pill unless the fabric is made from short, low-twist yarns. Rayon does not insulate body heat, making it ideal for use in hot and humid climates.
Rayon has moderate, dry strength and abrasion resistance. Like other cellulosic fibers, it is not resilient, which means that it will wrinkle. Rayon withstands ironing temperatures slightly less than those of cotton.
Modal is a second generation regenerated cellulosic fiber and a variation of rayon. Modal’s distinguishing characteristics are its high-wet strength and extra softness. It is sometimes referred to "as soft as a feather” and "the softest fiber in the world.” In addition to its use in general apparel, its softness makes it especially ideal for body contact clothing such as lingerie and undergarments.
Due to its high-wet strength, modal can be machine washed and tumble dried. Modal fibers are dimensionally stable and do not shrink or get pulled out of shape when wet like many rayons. They are also wear resistant and strong while maintaining a soft, silky feel. Modal fibers have found a wide variety of uses in clothing, outerwear, and household furnishings. They are often blended with cotton, wool or synthetic fibers and allow easy tone-in-tone dyeing (may be done with environmentally friendly dyes depending on the manufacturer).
Modal is about 50% more hygroscopic, or water-absorbent, per unit volume than cotton. It’s designed to dye just like cotton and is colour-fast when washed in warm water. Even after repeated washing, modal remains absorbent, soft and supple.
The colors in modal typically remain brilliant and strong. Graying, as with 100 % cotton textiles, does not occur. Bleaches or whiteners may not be necessary at all. However, if you do use these in any of your laundering, be sure you use environmentally friendly ones.
The smooth surface characteristics of the modal fiber make it impossible for mineral deposits from water, such as lime scum, to be deposited on the textiles thus preventing fabric hardening after repeated washings. This “dry rigidity” in some fabrics is caused by the mineral incrustation on the fiber after repeated washing.
Lyocell has numerous advantages over rayon and modal in its properties as well as its manufacturing process. One of the major “claims to fame” of lyocell is its ability to absorb excess liquid (perspiration) and quickly release it into the atmosphere. It does this while being resistant to developing odours.
The skin is the largest human respiratory organ. Lyocell supports the natural ability of the skin to act as a protective shell to regulate body temperature and maintain water balance. A subjective feeling of well-being depends considerably on moisture absorption and on surface structure of the fibers.
Nano fibrils are the key to the performance of lyocell. This is the first cellulose fiber to use this nano technology. The nano fibrils are hydrophilic (a strong attraction to absorb water) and optimize absorption of moisture with excellent cooling properties by releasing moisture to the air. Lyocell controls and regularly absorbs moisture, 50% more than cotton and even more than wool. By contrast synthetics do not absorb moisture.
Rougher fibers can lead to skin irritation. The microscopic surfaces of lyocell fibers, due to the nano fibrils, are smoother than the surfaces of modal, cotton and wool. It is the combination of this extremely smooth surface of lyocell and excellent moisture absorption that makes lyocell textiles feel so soft and pleasant to the skin, making lyocell ideal for active wear, clothing for sensitive skin and home textiles such as bedding.
Lyocell prevents the growth of bacteria (which causes odours) naturally without the addition of chemical treatment which may cause allergic reaction and are environmentally-unfriendly. Bacterial growth is prevented through the fiber's moisture management. When moisture is produced it is directly absorbed from the skin and transported to the inside of the fiber. Thus no water film is produced on the skin where bacteria could grow.
Clothes remain odour free for multiple wears much longer than cotton. This also means fewer washings and saving on water and energy as well as on the wear and tear that occurs on any fabric from the washing and drying processes. It is machine washable in cool water. Fabric softeners are not needed or recommended.
By contrast, synthetics have hundreds to thousands of times higher bacteria count over the same time periods as lyocell. Chemical additives are often used on synthetics and many cotton products to reduce the growth of bacteria.
Lyocell itself is hypoallergenic meaning that it is not likely to cause an allergic reaction in sensitive individuals. This is why it is used for clothing and home furnishings by individuals with Multiple Chemical Sensitivities (MCS) and those with allergy sensitivities, psoriasis, and neurodermatitis. It is also anti-static and doesn’t cling.
Environmental Friends or Foes? Are These Fabrics Sustainable?
Rayon, modal, and lyocell are produced from renewable cellulosic plants such as beech trees, pine trees, and bamboo. All three fibers are bio-degradable.
Specifically Ettitude’s bamboo lyocell which is produced from FSC certified bamboo plantation. Bamboo grows very quickly and without any artificial irrigation, pesticides, fertilizers or gene manipulation that may be used in “wood farms” for industrial use.
Lyocell manufacturing is an extremely environmentally friendly process and the most friendly of these three fibers. The revolutionary aspect of lyocell manufacturing is the recovery and reuse of up to 99.8% of the solvent and the remaining emissions are broken down in biological water treatment plants. In fact, the solvent is not acidic. The harmlessness of the solvent has been proven in dermatological and toxicological tests. One can put their bare hand in the solvent without harm (although it’s probably not advisable to leave it there). Also, no toxic substances remain in the fiber.
The fiber yield per acre from the bamboo used in the lyocell fibers is up to ten times higher than that of cotton. Also, cotton needs up to 10-20 times more water than required for lyocell fibers.
Of the total environmental impact of textile goods, much of it comes from the care of the textiles while in use. With lyocell fabrics, there is no need for fabric softener or whitening agents or bleach which add cost to the consumer and chemicals to our environment. Without these added agents, energy and water use can be decreased for spin and rinse cycles since shorter washing machine cycles can be used.
Lyocell is truly an environmental achievement in fiber production. It is derived from a renewable and sustainably harvested raw material, its manufacturing is sustainable, and its disposal is biodegradable to complete the full cycle.