What Are Viscose, Modal, and Lyocell Fibers?

Consumers love activewear because it's comfortable, breathable, and moves with them. What they don't love though, is the toll that polyester and other non-regenerative fibers are taking on the planet, which is one of the reasons eco-materials are in high demand. That's where viscose, lyocell, and modal fibers come in - a blend of natural and synthetic fibers, all three continue to gain popularity in activewear.

Viscose, modal, and lyocell are all semi-synthetic fibers, meaning they're made from natural cellulose that's been chemically processed. Often used in activewear, they are popular due to their versatility, eco-friendliness, and softness. Many consumers own a garment with one of the three fibers, but may not know it.

Although all three of these fibers have unique benefits, they are quite different from one another in physicality, application, and history. Let's dive in and take a closer look at each, helping you walk away with a sharper knowledge of semi-synthetic fibers.

Defining Viscose, Lyocell, and Modal Fibers

Before we look at any differences between each fiber, it's important to understand what they are and how they're made, especially since they are all types of rayon, which can be confusing in and of itself.

What is Viscose?

Viscose is a cellulose fiber that comes from wood pulp. It's also referred to as viscose rayon, artificial silk, and art silk, and because of its softness, it can be found in athleisure and some activewear.

Viscose has been around since the late 1800s, making it the oldest of the three fibers, and was created as an alternative to silk. It's often used in sportswear, but can be found in other garments like dresses, blouses, and bedding as well.

The Process of Making Viscose

Viscose production starts by breaking down cellulose from wood pulp using a process called hydrolysis. This creates what's called "dissolving pulp," which is then pushed through tiny holes (spinnerets), where it hardens and is pushed through to create long threads, which are then spun into yarn.

What is Modal?

Modal is a semi-synthetic fiber that's made from cellulose - namely beech tree pulp. It was developed in the 1950s and is often used as a more sustainable alternative to cotton.

You'll often find it in sportswear quite often because of its absorbency and resistance to shrinkage and color fading.

Modal is frequently blended with other fibers like spandex or cotton to create soft, stretchy, breathable, and absorbent fabrics. Even coming in a popular micro-modal arrangement, which is a thinner thread, giving it unique softness and strength.

The Process of Creating Modal

Modal is made in a process similar to that of viscose, where the cellulose is first broken down using hydrolysis. However, unlike viscose, modal isn't pushed through tiny holes to create yarn - it's extruded, which means it's pushed through a larger opening and cooled with water before being spun into yarn.

What is Lyocell?

Lyocell is a cellulose fiber that comes from wood pulp - usually eucalyptus, bamboo, or beech. It was developed in the 1970s and has only recently become popular due to its eco-friendliness.

Lyocell feels like a cross between silk and cotton and is known for being strong and durable yet soft, as well as breathable and absorbent, making it a popular choice for athletes.

The Process of Making Lyocell

Lyocell is unique in that it's made in a closed-loop system, meaning the chemicals used to dissolve the cellulose are recycled and reused.

The wood pulp is first broken down using a chemical process called hydrolysis. This creates what's called "dissolving pulp," which is then pushed through tiny holes (spinnerets), where it hardens and is pushed through to create long threads, which are then spun into yarn.

The main difference between the lyocell and the other two fibers is the spinning process, which uses a solvent instead of water. This makes it more efficient and less harmful to the environment.

Alright, so those are the building blocks of each fiber - let's look at their differences by comparison, so you can decipher the best garment to use each in.

What Is the Difference Between Modal and Lyocell?

The main difference between modal and lyocell is the spinning process; namely lyocell's use of a solvent instead of water. This makes it more efficient and less harmful to the environment. In some instances, like Tencel Lyocell, 99% of the solvent can be reused in each run.

Lyocell is also known for being stronger and more durable than modal, as well as being more absorbent.

Raw Material Differences Between Modal and Lyocell

While both are derived from trees, modal is strictly from beech trees, whereas lyocell can be made from a variety of trees, including bamboo, eucalyptus, and more.

These trees are important from an ecological standpoint when compared to a traditional textile like cotton - using a beech tree to make modal requires only 20% of the land you would need to get the same amount of cotton, and requires only 10% of the water needed.

But between modal and lyocell, lyocell's use of bamboo and eucalyptus is more sustainable. Bamboo is an incredibly fast-growing grass that doesn't require pesticides, and eucalyptus trees can grow in degraded soils, with low water, and atypically fast compared to beech, making them ideal for reforestation efforts.

How Modal Feels Compared to Lyocell

Both are blended so frequently, that it can be difficult to discern how they feel in comparison to each other when on their own.

But if you were to compare the two in pure form, the modal would be softer with a silkier feel, while the lyocell would have more of a cotton-like feel. From a look standpoint, the modal tends to have a more lustrous sheen to it.

The Disadvantages of Modal and Lyocell

While both fabrics are certainly more sustainable options than polyester and recycled polyester, they aren't the most eco-friendly fabrics on the market.

Lyocell, the youngest of the two, has been around for nearly 50 years, and a ton of textile innovation has happened since - like Seawool, which is a blend of recycled polyester and oyster shells. Or even SeaCell, which is recycled polyester, and seaweed that can pass on nutrients from the fabric to wet skin.

Additionally, the production of modal and lyocell both depend on the individual manufacturer to avoid poor timber harvesting practices and responsible solvent and water practices. Some manufacturers of modals specifically have been brought into question for using wood from

de-forested land.

What Is the Difference Between Viscose and Modal or Lyocell?

Depending on the type of fiber you need to do the job, modal and lyocell have their own advantages. But bother are sustainable options. So how does viscose rayon, the 1800s pioneer of cellulose garments compare?

Raw Materials Used In Viscose Rayon

Well, first off, all three - viscose rayon, modal, and lyocell - are made from the cellulose found in plants. Viscose rayon primarily comes from wood pulp - usually from fast-growing trees like eucalyptus, pine, and spruce, but can also be made from cotton and bamboo.

The Feeling of Viscose Rayon

If modal is the silkiest and lyocell is the "cotton-iest," then viscose rayon would be somewhere in the middle.

It has a soft and smooth feel but isn't as lustrous as the modal. And while it's more absorbent than polyester, it's not as absorbent as cotton or lyocell.

Viscose Rayon Process Compared to Modal and Lyocell

Wood pulp is shaped into cellulose by a chemical solution. It's then extruded through tiny holes and forced through a chemical bath to solidify it, and then wet-spun. The yarn is then put through a drying process and finally wound onto bobbins.

The main difference in the viscose rayon process is that it uses harsh chemicals at each stage - including sulfuric acid, carbon disulfide, and chloroform. These chemicals are harmful to both the environment and the workers exposed to them daily.

The Disadvantages of Viscose Rayon

The main disadvantage of viscose rayon is the environmental impact of its manufacturing process.

Not only does it require large amounts of water (estimated at around 200 tons for 1 ton of fabric), but the chemicals used can pollute both air and water supplies.

Additionally, because viscose rayon is made from wood pulp, it often requires the use of fast-growing trees - which can lead to deforestation, if not managed properly.

While viscose rayon, modal, and lyocell are all made from cellulose, they each have different properties that make them better suited for different purposes.

Athletic Wear from Sustainable Fabrics

If sustainably produced athletic wear is at the top of your shopping list, there are

plenty of options. Though you should be mindful to shop from reputable manufacturers and

clothing companies that truly are using sustainable practices.

Should you choose to go the route of these rayon fibers, sustainability is a top consideration, which it should be, since consumers have deemed it critical in their activewear purchase drivers, then you'll need to balance the fiber with the purpose of the garment.

Outside of that, you now know that viscose rayon is the least sustainable option, due to the harsh chemicals used in its production, while lyocell is the most sustainable option, due to its closed-loop production process.

Modal is somewhere in the middle, with a few sustainability concerns but overall a good option.