36% bio-based content, which is biodegradable via industrial composting at the end of life. Cirql said that in its mission to help footwear brands reach climate and sustainability goals, its “commitment is to offer trusted, scalable footwear material solutions to keep shoes out of landfills”. Materials companies have been
developing bio-based polyurethane and TPU materials for a while, and some have now taken material sustainability a stage further. Algenesis Labs has started up a US-based pilot plant for Bio-Iso polyurethane feedstock, the first 100% biogenic carbon isocyanate that is made from plants, calling the breakthrough “a disruptive innovation in polyurethane chemistry”. Polyurethanes are produced by reacting isocyanates with polyols. Plant-derived polyols are already available from a few companies, including Algenesis, so its development of a non- petroleum equivalent in isocyanates opens a route to achieving totally bio-based content in applications such as shoe soles. “Bio-Iso is the foundation for a new class of plant-based polyurethanes, enabling manufacturers to align their products with global sustainability goals and meet increasing regulatory and consumer demands for safer, eco-conscious materials,” said the company in an August announcement. “This isn’t just a greener alternative.
Bio-Iso represents a fundamental shift in how we think about polyurethane production,” said Dr. Stephen Mayfield, CEO at Algenesis. “Combined with our Soleic polyol, Bio-Iso now enables a 100% bio-based TPU – validated through ASTM D6866-24 analysis by Beta Analytic – that delivers truly circular, sustainable materials without compromising durability or performance.”
Bio-Iso is made from plant-based
dicarboxylic acids and manufactured without the use of phosgene, unlike the process to produce isocyanates from petroleum. Algenesis says its novel process is both modular and scalable. It is now scaling the Bio-Iso process at its San Diego facility, and is seeking strategic partners to support global industrial-scale commercialisation. Early partners will gain priority access to Bio-Iso materials and options for future volume.
TPU pellets made using Soleic bio-based polyols from Algenesis Labs. Image: Algenesis
Cirql Zero36 midsole foam made from 36% bio-based content, which is biodegradable via industrial composting at the end of life. Image: Cirql
Biodegradable Algenesis has created Blueview shoes with Soleic-based polyurethanes which make the shoes compostable. At the Polymers in Footwear conference, Nick Sandland, Chief Business Officer at Algenesis, said the biodegradability of Soleic generates only non-toxic by-products. This offers a solution to the problem of microplastics that are released into the environment from shoe wear. He said tests had shown Soleic systems do not generate persistent microplastics.
Soleic thermoset polyurethane and thermoplastic polyurethane materials are being used in insoles, midsoles, outsoles and other shoe applications worldwide, which counters any perception that bio-based materials are inferior, he said. “We’ve gone out of our way to demonstrate the durability of our products,” he said. And durability is combined with 100% biodegradability as tested to ASTM D5338. The Blueview Pacific loafer was the
company’s first biodegradable shoe, with insoles and sole elements made from Soleic polyurethane foams, a heel counter made from Soleic TPU and other parts made from natural fibre materials. The project to develop and produce this first shoe “highlighted the importance of choosing the right manufacturing partners”, said Sandland.
A hightop shoe called Blueview Atlantic,
with similar materials and construction to the Pacific, is being launched this year. One difference with the Atlantic is that the cotton canvas upper is coated with a layer of Soleic TPU and a layer of durable water repellent. Sandland said slides have also been developed which use Soleic foams with 51-57% bio-based content.
Cost question Patrick Van Waes, Global Marketing Director at Primient Covation, asked at the conference: “Are consumers ready for plant-based performance?” The answer he gave, based on a survey of over 1,000 US shoe buyers, was: “Yes… but…they need to be informed what it means for them.” The survey was conducted by Insite Insoles with support from product testing consultants Mesh01 and Primient Covation, producer of Susterra bio-based propanediol (PDO), an alternative to petroleum-derived PDO in polyol production. A key finding of the survey was that 81% of people said they would be willing to purchase shoes which have bio-based content that increases the cost but provides the same quality and is better for the environment. “I was astonished with the responses,”
said Van Waes. A big mark-up in price is not needed when using bio-based materials, he said. A 10% price premium received the most responses in the survey. He suggested
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