In the guide below though, we outline how eco friendly or sustainable each type of fibre might be.
The information in the guide below is mainly related to the use of these fibres in fabrics, clothing and textile products.
Summary – Eco Friendliness & Sustainability Of Rayon, Viscose, Lyocell & Modal
Firstly, What Are Rayon, Viscose, Lyocell & Modal?
As a very brief summary:
Rayon comes in different types and forms, but rayon is essentially a regenerated cellulose fibre
Viscose rayon is a form of rayon that is made using the viscose process
Lyocell is a form of rayon that is made using the lyocell process
And, modal is a form of rayon that is made using the modal process
Read more about rayon, and the viscose, lyocell and modal processes in this guide.
A Note On Generic Lyocell & Modal vs TENCEL & Lenzing Lyocell & Modal
Some important points to outline with these fibres are:
– There’s fibres that are generically called lyocell and also modal, because they use the general lyocell or modal processes (and this is why definitions and descriptions of lyocell and modal online tend to be generalized definitions and descriptions)
– Lyocell and modal fibres though can be made by a number of different fibres manufacturers
– Each individual lyocell or modal fibre product from different lyocell or modal manufacturer/producers will not only have it’s own set of features and traits, but also it’s own sustainability rating and other ratings, depending on how it’s made by the producer/manufacturer. We elaborate on this point, pointing out that each individual fibre product needs to be assessed individually, and give an example of a specific Lyocell fibre product from a specific fibre manufacturer/producer in this guide.
Where we are referring to TENCEL Lyocell or TENCEL Modal fiber products specifically, we’ve identified this clearly, otherwise we are referring to generic lyocell or generic modal, that uses the general lyocell or modal process.
As branded fiber products, Lenzing and TENCEL Lyocell and Modal fiber products may be some of the most eco friendly and sustainable fiber products right now.
Beyond their eco and sustainability features, Lenzing and the TENCEL brand are transparent with the range and depth of information they share publicly on their website as well, such as their sustainability practices.
How Eco Friendly & Sustainable Are Viscose, Lyocell, & Modal?
Viscose using the traditional viscose process might be the least eco friendly and sustainable of the three
Although, some manufacturers use a newer viscose process with several sustainability improvements, which increases the overall sustainability rating of the end fibre
Lyocell and modal are considered to be more eco friendly and sustainable than viscose in general
Lyocell may be slightly more eco friendly and sustainable than modal when it uses an organic solution to dissolve cellulose, as this organic solution replaces the sodium hydroxide used in modal
The viscose process has been identified as having social and environmental concerns in the past
A large factor in this stems from the chemicals used, such as carbon disulfide (amongst other chemicals), which can impact worker safety, and the environment
Over the past few decades though, specific countries and companies have taken steps to clean up and make the viscose process safer
One focus has been on better control and management of carbon disulfide, with other changes being treatment of waste water and pollution
Not all viscose rayon production has become cleaner and safer though – cost has been a barrier for some manufacturers, and some countries still have a lack of regulations or standards
Lyocell was developed for the specific purpose of introducing a more eco friendly and less harmful process than the traditional viscose process (although, there were some other goals relating to fibre performance/traits, and cost too)
Lyocell can also be more sustainable and eco friendly than modal too
Much of this has to do with the chemicals or solvents that lyocell uses compared to viscose or modal i.e. lyocell’s chemicals or solvents may be less toxic, hazardous or damaging
Lyocell can be a fully organic form of rayon when it uses organic and non toxic solvents
Having said that, some sources indicate that some lyocells from some countries can have questions over their dyes, anti-pilling and finishing chemicals and toxicity of the by-products from lyocell production
Modal is generally more eco friendly and sustainable than traditional viscose rayon because it cuts out unnecessary steps, and reduces overall waste.
Modal may also use lower concentrations of sodium hydroxide compared to viscose rayon, which may make it more sustainable and eco friendly
*Lenzing Viscose, Lyocell & Modal Processes
Something to note is that Lenzing has their own viscose, lyocell and modal processes for their different fibre products, and these processes may differ from generic processes (and the ones described above).
Lenzing makes some comparisons between those individual processes on that resource page.
Main Factors The Might Impact The Eco Friendliness & Sustainability Of Viscose, Lyocell & Modal
– The individual manufacturer of the fibre, and how eco friendly and sustainable their practices and processes are
– The chemicals or solvents used during processing of each fibre
– The country or regions each fibre is made in – different countries have different social and environmental regulations and standards
– In a finished textile product or a finished fabric, whether the fibre is blended with another fibre or not (as this changes the footprint of the finished product)
How Eco Friendly & Sustainable Are Rayons In General Compared To Other Types Of Fibres?
It depends on the type of rayon that is used obviously
But, in general, rayons might be slightly more eco friendly and sustainable than some synthetic fibres, and slightly less eco friendly than some natural fibres
Guarantee Of Standards Across The Supply Chain In Rayon Products
Something that is important when buying any rayon is to get a guarantee on the standards of how that rayon has been sourced and produced across the supply chain.
This can be an issue for some rayon products
Transparency by the rayon manufacturer in terms of the information they provide, and the supply chain traceability systems technology they have in place can help.
And, third party certification programs and standards can help too.
What About The Eco Friendliness & Sustainability Of Other Fibres & Fabrics?
Other Factors That Can Impact Fibre Sustainability & Eco Friendliness
Eco Friendliness & Sustainability Of Rayon
What Is Rayon?
Some examples of rayon include viscose, lyocell, modal, bamboo rayon, acetate, plus other forms and types of rayon.
How Sustainable & Eco Friendly Is Rayon?
It largely depends on the type of rayon in question.
But, when just generalizing rayon as a cellulose based fibre that undergoes chemical processing break down cellulose into a soluble mix that can then be regenerated into a fibre …
Rayon might be more sustainable than some synthetic fibres
And, rayon might be less sustainable than some natural fibres
The sourcing of rayon cellulose or other organic material used as the base of the rayon fibre has potential to be more eco friendly and sustainable than for example the sourcing of petrochemical derived compounds used to make monomers and polymers for some synthetic fibres
But, there are some natural fibres that may be sourced naturally, and may involve mechanical harvesting, mechanical retting, and may involve the use of either no chemicals, or less harmful chemicals during fibre production (compared to rayons). Some jutes and some linens may fit this description, amongst other natural fibres
These are generalisations though – each specific type of rayon has to individually be compared to each specific type of synthetic or natural fibre it’s being compared to
From shopvirtueandvice.com: Rayon is more sustainable than petroleum synthetic fibers like polyester and nylon. But, is not as sustainable as organic cotton and hemp.
Major Variables That Might Impact The Sustainability Or Eco Friendliness Of Rayon
May include but not limited to:
– The type or form of rayon
E.g. viscose rayon, lyocell rayon, modal rayon, bamboo rayon, rayon acetate, and so on
– The type of cellulose used
This includes the cellulose material used itself, and also how it’s grown
Examples of different cellulose material can include wood cellulose, bamboo cellulose, and other types of cellulose
Even different types of wood cellulose can be used (which come from different types of trees), such eucalyptus wood, or beech wood, as a few examples
In addition, how the cellulose material is produced matters …
If wood is used for cellulose, how are the trees grown? Are tree plantations sustainably certified and managed?
Being able to send the leftover wood material (that can’t be used for wood pulp) to a biorefinery for conversion into bio energy many further help with the sustainability rating.
– The specific chemicals or solvents used in fibre manufacturing/production
This mainly includes the break down of cellulose into a pulp or soluble mix (pulp production), but can also include retting (retting can be mechanical retting, or chemical retting), and the fibre spinning or extruding process after cellulose has been broken down.
Different chemicals and solvents have different potential for harmful, toxic or hazardous impact on the environment, and human workers.
For example, carbon disulfide is often listed as a potentially harmful chemical that has been used for the viscose process in the past
– Practices used during fibre manufacturing
Are chemicals and solvents released into the environment untreated, or are they captured and re-used?
Is water and waste water released into the environment untreated, or are they captured, and either treated, or re-used?
Is processing overall closed loop, or open loop?
Is the energy used from fossil fuels, or renewable energy?
Other Information On The Potential Sustainability Of Rayon
[On the biodegradability of rayon … ]
The biodegradability of various fibers in soil burial and sewage sludge was evaluated [and] Rayon was found to be more biodegradable than cotton, and cotton more than acetate.
The more water-repellent the rayon-based fabric, the more slowly it will decompose
[On fibres found in deep ocean areas … ]
Different studies showed different results. Some studies showed rayon as the most commonly found fibre, whilst others showed cotton as the most commonly found]
What Might Make Rayon More Sustainable & Eco Friendly
Might include but not limited to:
– Using natural and/or renewable sources of cellulose
– Sourcing cellulose from sustainably managed (and/or certified) farming operations e.g. sustainably managed forest plantations
– Using mechanical retting over chemical retting
– Pulp production and fibre production processes that use more eco friendly and less harmful chemicals and solvents
– Using closed loop production that captures, treats and/or re-uses resources like waste water, but also chemicals and solvents
– Using renewable energy for production processes
– Producing fibres that are of good quality, and durable, so that they last longer in the product or application they are used for (and the sustainability footprint can be averaged out over a number of years)
– Producing fibres that are biodegradable and compostable across a rang of conditions and environments
– Fibre producers/manufacturers being transparent on their website about their sourcing, supply and production practices and standards.
– Third party certifications can help establishing other sustainability and social standards that the fibre production may meet
– Having some sort of traceability system (like blockchain) for the supply chain used
– Have sustainable processes in place for the rest of the fibre or product lifecycle i.e. at the various other stages of supply, production, use and disposal
Eco Friendliness & Sustainability Of Viscose
What Is Viscose?
We explain what viscose is and how it’s made in this guide.
Is Viscose Eco Friendly & Sustainable?
It depends on the type and grade of viscose being assessed.
The cellulose material used, and the chemicals and solvents used in the viscose process are significant variables to the sustainability.
For example, different types of wood cellulose could be used, but so can a cellulose source like bamboo.
In terms of chemicals and solvents, carbon disulfide is often identified as a potentially toxic and harmful chemical for production workers and the environment.
Caustic soda and sulphuric acid are sometimes mentioned as having the ability to be toxic or hazardous in some instances too, along with sodium hydroxide if it’s used.
Where the viscose is produced geographically matters too – different countries have different environmental regulations on fibre production, and some are less strict than others in enforcing these regulations.
It’s also worth pointing out that over the last few decades, the viscose process has gotten more sustainable and eco friendly (and less harmful) in several countries.
Some of the changes in newer viscose processes are the use of a carbon disulfide alternative/substitute, control and management methods of carbon disulfide when it is used, and other sustainability measures like treating or managing waste water.
From a practical point of view, worldwide, viscose is still one of the more commonly used rayon processes because of how cheap it can be to produce
Wood cellulose can help keep the cost down, but, so can lower standards on environmental impact and human safety (methods and processes for higher standards can be more expnsive for producers)
More Information On The Sustainability Of Viscose
[Viscose rayon is the dirtiest form of processing rayon … partly because of carbon disulfide use in the past]
[Viscose rayon has become more eco friendly and sustainable over the years, but one of the issues with viscose rayon is that because it’s hard to guarantee how the viscose rayon has been sourced and produced, or guarantee what has happened through the supply chain – you can’t be sure what you’re buying unless you’re buying from one specific company that is transparent with their processes and practices]
Surprisingly, viscose rayon may be one of the fastest decomposing fibres.
[In terms of biodegradability, one study] found that viscose rayon actually decomposes faster than cotton 6 weeks vs 11 weeks. But, modal and tencel tend to take a bit longer at about 4 months decompose only 1/2 of the fabric
Improvement Of Viscose Process Over Time
[Viscose rayon has become a lot more eco friendly in recent years]
… the original viscose process generates large amounts of contaminated wastewater.
Newer technologies use less water and have improved the quality of the wastewater.
[Traditionally, viscose rayon has used carbon disulfide, and wikipedia.org goes into the potential toxicity issues to humans carbon disulfide may cause during some viscose production around the world where it’s used]
[Additionally, in places where carbon disulphide is still used for viscose rayon] Control technologies have enabled improved collection of carbon disulfide and reuse of it, resulting in a lower emissions of carbon disulfide [but] These have not always been implemented in places where is was not legally required and profitable
[Emissions abatement and other carbon disulfide controls that control pollution and protect worker safety have also been implemented, but in some places the cost of these practices has been a consideration for production]
[There may still be some] concerns for worker safety [with viscose processes around the world too]
The viscose rayon process uses carbon disulfide to convert cellulose into cellulose xanthate, which is soluble in aqueous alkali solutions, before forming fibers in an acidic coagulation bath.
In recent years a new solvent system comprising N-methylmorpholine N-oxide has been used to dissolve cellulose, which is a more environmentally friendly process for the production of cellulosic fibers.
What May Make Viscose More Sustainable & Eco Friendly?
Viscose may be more eco friendly and sustainable:
– In places where carbon disulfide is substituted for another chemical or solvent, such as N-methylmorpholine N-oxide, to dissolve cellulose
– Where carbon disulfide is controlled and managed with various methods when it is used
– Closed loop processing (where waste water is treated and re-used, and chemicals are captured and re-used) can also help with sustainability over open loop processing.
– Where worker safety and health is protected
– In the case of bamboo specifically, bamboo rayon using the viscose method can be substituted with bamboo rayon using the lyocell method, or can use mechanical retting and more natural processing, and perhaps be more sustainable.
Some Sources Question How Harmful Chemicals Used In Rayon Viscose Actually Are
bambootextiles.com.au indicates that many of the chemicals used in viscose rayon production may not pose a significant risk:
The two main chemicals used in the process [when it comes to bamboo rayon viscose production] are sodium hydroxide and carbon disulfide … [and] With adequate ventilation [carbon disulfide] is not a problem these days and it breaks down when in contact with the natural elements.
Neither carbon nor sulfur are poisonous elements.
Sodium hydroxide is also known as caustic soda, and it is true that it is strongly alkaline and will react with many substances … however, it is not toxic at all …
So, a thorough assessment of how harmful or toxic each chemical actually is, should be done to get an accurate view of whether or not they need to be managed better.
Eco Friendliness & Sustainability Of Lyocell
What Is Lyocell?
We explain what lyocell is and how it’s made in this guide.
How Sustainable & Eco Friendly Is Lyocell?
Lyocell was developed with the specific intent of being more eco friendly and less harmful to humans than the viscose process (although, reduction of costs, and additional functions for fibre performance were also goals)
In comparison to viscose, it uses different chemicals and solvents to dissolve the cellulose.
Lyocell doesn’t use carbon disulfide, and the lyocell process uses a direct solvent rather than indirect dissolution such as the xanthation-regeneration route in the viscose process.
In comparison to modal, Lyocell production uses a different solvent to extract the cellulose from the wood: a chemicals like sodium hydroxide (caustic soda) might be replaced by a non-toxic organic compound, N-methyl morpholine N-oxide (NMMO).
This organic solvent is said to be easier to filter and re-use in a closed loop, which is better for the environment.
For this reason, it could also be more sustainable than some other types of rayon that use more harmful or more toxic chemicals or solvents.
Further to this, some sources say lyocell is the only form of rayon that can be considered to be purely organic; since the cellulose used to make this fabric isn’t chemically altered during the production process.
Lyocell can be made from different types of trees, including beech trees and eucalyptus.
One of the sustainability issues from an economic or practical perspective, could be cost and being able to scale it (it is more expensive than the viscose process)
Since there is little waste product, [the lyocell] process is relatively eco-friendly, though it is energy-intensive (wikipedia.org)
More Information On The Sustainability & Eco Friendliness Of Lyocell
[The lyocell process, dissolves the cellulose in an amine oxide; and is less toxic because the process does not use highly-toxic carbon sulfide]
[It may be more expensive than viscose, and not as widely used]
The development of lyocell was motivated by environmental concerns; researchers sought to manufacture rayon by means less harmful than the viscose method
In 1992, Courtaulds developed a new process for the production of regenerated cellulose fibres, the Lyocell process.
Encouraged by a growing concern for environmental production coupled with reduction of costs, the new fibre was also engineered to bring additional functions to its performance
[General lyocell can also use different types of cellulose – like for example wood, but also materials like bamboo]
[General lyocell doesn’t have the] rigorous compliance and strict supply chain control
[Lenzing branded lyocell on the other hand may have transparent processes]
[Bamboo rayon can be made via the viscose process or via the lyocell process, and the lyocell process] which is a closed loop system [is] much more sustainable
From elkieark.com: ‘Some lyocells that come out of China might have some questions over them – apart from the production process, you have to watch out for the dyes, anti-pilling and finishing chemicals, as well as that by-products from the lyocell production are also non-toxic’
Lenzing’s Own TENCEL Lyocell Fibre Product
Lenzing also produces a TENCEL branded Lyocell which has a number of claimed sustainability benefits (such as closed looped production, and sourcing renewable cellulose material from sustainably managed forests, just as a few examples).
… Lenzing Fibers [describes lyocell as a] “solvent spun fiber” that keeps the cellulose structure closer to that found in nature
Paraphrased from Lenzing’s ‘Technologies’ page about their own lyocell process: ‘[Lyocell has been used at an industrial scale for 25 years, is environmentally responsible, is less complex than viscose or modal processes, and dissolves and processes the wood pulp in a closed loop without any chemical derivatisation]
In contrast to the viscose process, an organic solvent called N-methylmorpholine-N-oxide (NMMO) is used to directly dissolve the pulp without any chemical change. For this reason, it is considerably simpler than viscose production.
Lenzing lists other sustainability features of their Lyocell process on their ‘Technologies’ page.
From undershirts.co.uk: The Austrian firm Lenzing [make TENCEL Lyocell] from fast-growing Eucalyptus trees from sustainably managed forests.
Some Lyocell Processes Still Use Potentially Harsh Chemicals Though
While production of lyocell fibers is generally eco-friendly and environmentally sustainable, the transformation of lyocell fibers into fabric and garments can use many or the same harsh, and even toxic, chemicals and processes used in conventional garments.
This is because of two properties of lyocell: it doesn’t always accept dyes well, and it has an inherent tendency to fibrillate or “pill”.
Economic Value Of Lyocell
– Value Of The Lyocell Industry/Market
The Lyocell Fiber Market size was over USD 850 million in 2016 and is anticipated to witness growth at a CAGR of around 8% over the forecast timespan owing to its extensive usage in various end-use industries including home textiles, apparels, and medical equipment (gminsights.com)
The global lyocell fiber market is expected to grow at a CAGR of close to 8% during the period 2018-2022 … (businesswire.com)
Eco Friendliness & Sustainability Of Modal
What Is Modal?
We explain what modal is and how it’s made in this guide.
Is Modal Eco Friendly & Sustainable?
Like other forms of rayon, it depends on the manufacturer making it.
But, in general, it might be more sustainable than viscose, and less sustainable than lyocell.
From a practical perspective, modal might be more expensive than viscose rayon, but on par with lyocell. But, some sources indicate modal can be cheaper than viscose in some instances.
[Overall] … modal rayon is not an inherently sustainable or environmentally-friendly material.
While the manufacture of this product has the potential to be sustainable under certain circumstances, it is up individual manufacturers to follow the manufacturing processes that will result in environmentally-friendly fabrics
[When] cellulose [is obtained] from trees that have been grown on land that is not suitable for any other agricultural purposes [modal can be more sustainable]
Modal Compared To Viscose
Modal is produced in a manner like that of viscose rayon, but without most of the wasteful and harmful processes.
Two of the main differences of modal that may make it more sustainable and eco friendly than viscose might be:
– Using different chemicals and/or solvents during fibre production, or cutting out certain chemicals and/or solvents.
Modal is more environmentally friendly than viscose because lower concentrations of sodium hydroxide are used to make it (which results in the production of less toxic waste)
– Cutting down the number of steps in the modal process compared to the viscose process, making the modal process quicker, simpler and having less waste.
As a result of this, there may also be less chemical treatment processes
More on the modal process compared to the viscose process, from sewport.com:
[Modal as a type of rayon] is nearly identical to viscose rayon [, however, modal is a slightly more eco friendly and sustainable process that is simpler, includes less steps, and also doesn’t produce as much waste]
… far lesser concentrations of sodium hydroxide are used to create modal rayon than are used to create viscose rayon, which results in the production of less toxic waste
… [there’s also] lesser concentrations of caustic soda … used to dissolve and purify the cellulose …
However, the modal fabric manufacturing process still uses the step called “xanthation,” which involves the application of carbon disulfide to cellulose during production. Carbon disulfide [can cause a number of potential issues for humans and the environment]
In recent years, rayon manufacturers have taken steps to reduce the impact of carbon disulfide on workers and the environment [and sewport.com lists examples of these steps]
[Modal made in China may be cheaper, but also less environmentally friendly, and involve workers’ rights issues because …] the government of Communist China is notoriously lax in its environmental and workplace safety standards. [This should be considered when working with Chinese modal producers or suppliers]
Factors That Specifically Impact Modal’s Sustainability
– The modal fibre producer/manufacturer
The company sourcing and producing the modal matters.
In general, the Modal fibre produced by TENCEL is considered to be quite eco friendly and sustainable compared to other fibres.
– The country where the modal is produced, and the chemicals or solvents used
Some countries may have lax environmental standards, and workplace safety standards
In some of these countries, either the chemicals used could be toxic/hazardous, or the management of waste could be problematic
For example, sodium hydroxide or caustic soda, carbon disulphide and sulfuric acid could all be used in the modal process in some countries
– The cellulose material used
Some modal fibres may use beech wood specifically, whilst other rayons may use different wood material types
Other Information On The Sustainability Of Modal
Some sources say the processing stage of modal may use more energy than natural fibres:
Processing the beech wood into a cellulose fiber is a man made process which uses more energy than processing natural fibers
Modal is generally considered a more eco-friendly alternative to cotton because beech trees don’t require much water to grow and therefore the production process uses about 10-20 times less water (masterclass.com)
While Lenzing leads the way, there are other companies that produce this type of rayon.
The production of modal takes place in countries like China, India, Indonesia, and Pakistan—but without the strict standards used by Lenzing.
In some areas of the world, the production of modal fabric occurs with government standards that are more lax than in others. This can have an impact on sustainability and worker conditions, given the heavy use of chemicals in production.
[So, it depends the the modal fibre manufacturer and how sustainable their sourcing and fibre manufacturing processes are]
It’s growth is more sustainable than that of cotton, and it’s responsible for yields up to ten times as high. It also uses 20 times less water! (sustainablejungle.com)
Lenzing’s Own Modal Fiber Product
It has several brand specific sustainability and eco friendly features, and uses Lenzing’s general sustainability practices for production.
On example of many is that Lenzing might be able to make use of their biorefineries to use the rest of the tree and wood material that is left over after the cellulose is obtained, and co-products and energy can be produced with it. Other modal producers may only use the wood cellulose from trees used to source cellulose and throw the rest of the tree material away
[From 2010 to today, Lenzing was also able to produce Modal with ecological advantages]
In 2012 Lenzing presented Modal Color, a modal fiber with significant ecological advantages in the dyeing process and without losing its color intensity even after repeated washes
Economic Factors Related To Rayon, Viscose, Lyocell & Modal
Production Of Rayon, Viscose, Lyocell & Modal
– Total Production Share Of All Fibres
We don’t have the specific production numbers for these fibres right now.
Miscellaneous Economic Benefits
Plant based fibres may be the only type of fibre that can be produced in some regions of the world, and might offer other benefits too, such as being able to be grown alongside or in rotation with another plant, crop, or other agricultural product.
This may be an indirect economic benefit of cellulose based rayon fibres sourced in some regions of the world.