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Pliant

Pliant - NFW's 100% bio-based outsoles / Source: Natural Fiber Welding
FlexibleNorth AmericaPliantRecyclableRubberStrongTextilesWaterproof

WHAT WE SAY:

Completely fossil free footwear is fast approaching, and Natural Fiber Welding is leading the charge. 

Pliant, a natural rubber shoe sole is durable and recyclable, and the latest nutrient-based material to emerge from the NFW lab. While most shoes use petrochemical soles, Pliant is made entirely from plants, free of fossil fuels and microplastics, and able to break down into natural nutrients at the end of its life.

We're sold already, but have a couple of queries. How quickly can Pliant transform the footwear industry, and will climate change affect the global rubber supply before innovations such as these can slow it down? We don’t know, but with the first Pliant-soled sneaker already on the market, we have high hopes. 

Pliant

WHAT IS PLIANT?

  • In emailed questions, Natural Fiber Welding (NFW) claims Pliant “is the most sustainable shoe sole ever made: natural, recyclable and scalable.” The material is made primarily from sustainably sourced Rubber, and includes other inputs, such as “nutrients, minerals (as a performance additive) and natural pigments.”
  • Natural rubber comes from the hevea brasiliensis tree. The tree is tapped like maple trees for syrup and a white, milky liquid—latex—flows out. The liquid is dried in sheets and then used to make rubber products.
  • The properties of natural rubber include elasticity, water resistance, resiliency and durability, and these all apply to Pliant. NFW states that Pliant is “high in grip, very flexible, with excellent tensile strength.”
  • At the moment, Pliant is developed for casual and athleisure footwear, but formulations are developing for performance materials.
  • NFW sources its rubber from “responsibly managed plantations in Thailand, with some of the best health, safety and environmental practices in the industry.” It uses a “bio-curative agent, instead of traditional rubber vulcanising agents” - i.e. fossil fuel agents - to transform the raw material into shoe soles. The brand sees itself “like a chef in a kitchen that builds directly from what nature has already produced.”
  • The company is not targeting home compostable certification because it isn’t worried about the speed of degradation. At present, NFW is studying how its materials break down, how degradation time scales differ in different environments and the safe limits of nutrients in soil, to fully understand the material's end-of-life. 
  • Rather than disposability, the brand focuses more prominently on durability and long lifespans of products, and recyclability. NFW has patented a recycling method that it describes as “highly efficient mechano-chemical processing.” Essentially, it’s like chewing food: grinding up natural polymers so they can be remoulded into new products. 
  • NFW is headquartered in Peoria, IL and closed an USD 85 million Series B round in April 2022 for scaling its natural materials and manufacturing. The company envisions converting the whole of the footwear industry to using Pliant and foresees partners on many continents who can mould and mix materials. Existing infrastructure can also be used, rather than building new machinery, meaning Pliant is more easily adoptable at scale. 

KEY PROPERTIES:

  • Flexible
  • Recyclable
  • Strong
  • Waterproof

INDUSTRY:

  • Textiles

AVAILABILITY:

Partner Trials

DIVE DEEPER:

  • If the footwear industry was a country, it would be the 17th largest polluter in the world. The average sneaker is made predominantly from fossil fuel plastic - synthetic rubber soles, synthetic polyester uppers and plastic-based eyelets - and because the construction of a shoe is so complicated, involving glues and stitching, most shoes are impossible to recycle. Meaning they end up languishing on the planet for hundreds of years to come.
  • Focusing specifically on synthetic rubber used in footwear—which is most footwear—Bloomberg reports that in 2020, the market size for synthetic rubber was USD 18.4 billion and is projected to reach USD 24.9 billion by 2028. The primary driver for this increase is the footwear industry. 
  • Synthetic rubber is a major source of microplastics. Overall, it is one of the top three microplastic sources found in the ocean, with car tyres the biggest contributor to the problem. Microplastics are tiny plastic particles that have now been found almost everywhere on earth, in our food and drink, and in our bodies and blood, and the blood and bodies of animals. 
  • Most rubber created today (70%) is made from fossil fuel chemicals. This was a necessity during World War II, when the West’s rubber supply was cut off from Asia, but it isn't a necessity today, and NFW's Pliant is paving the way for the return of natural rubber. 
  • The rubber tree is native to South America and the substance was first used by Amazonian tribes to make balls for games, among other things. South American leaf blight decimated the rubber tree population on the continent and since the 1930’s, rubber production has been focused primarily in Southeast Asia.
  • Although strict protocols are in place, environmentalists are concerned leaf blight will eventually make the jump to Southeast Asia where it could decimate rubber production there too.
  • From a design perspective, natural rubber is said to have many enhanced properties over synthetic rubber. These include a higher tensile strength and tear resistance, chemical and fluid resistance, and heat tolerance. 
  • Growing rubber has its own environmental and societal issues that can't be ignored, however, including deforestation, high labour, and low prices set by the Shanghai Futures Exchange, rather than real-time supply and demand. Most natural rubber (85%) is produced on small farms throughout Southeast Asia, and when sourcing the material, it's important to prioritise farms that aren’t on recently deforested land and are paying fair wages. 
  • Pliant's first commercial use is in UNLESS Collective's The Degenerate sneaker, a 100% bio-based trainer that launched in December 2022. The sneaker is made up of NFW's four core materials - Mirum, Clarus, Pliant and Tunera, and took just over two years to develop. 
Rubber drying production / Source: Shutterstock
Pliant is flexible, and high in grip and tensile strength / Source: Natural Fiber Welding

KEY FACTS:

85%

of natural rubber is produced on small farms throughout Southeast Asia

70%

of rubber created today does not come from the hevea brasiliensis tree, but instead from fossil fuel-made chemicals

$24.9bn

According to Bloomberg, the synthetic rubber market is projected to reach USD 24.9 billion by 2028

Key Questions to Ask:

What other materials are you working with?

If you plan on using a natural product like Pliant, do you plan to use other natural materials as well? Eliminating one fossil fuel-made component from your footwear is a good start, but turning the whole piece into natural components is even better. Look to the Degenerate sneaker for inspiration. 

What is the end-of-life plan for your product?

If you do plan on using non-NFW materials for the other parts of your product, how do you envision its end-of-life, a vital component of the design process now Extended Producer Responsibility laws are coming into play? Pliant is made to be recycled or slowly degrade in the soil, providing vital nutrients. Do you have a take-back scheme in mind to get your used products back from customers, so the footwear can be disassembled and Pliant sent back to NFW for recycling? Something to bear in mind. 

How soon would you like to work with Pliant?

According to Dr. Haverhals, the company has received over 1,500 requests to work with its products as of October 2022. If you're on a tight timeline, Pliant may not be the right solution for you, but we urge people to ask anyway. If it doesn't work today, it most likely will do in the near future.

MEET THE MAKERS:

Natural Fiber Welding

KEY PRODUCTS
ClarusCorkMirumPliantRubberTunera
LOCATION
North America

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