Sometimes the simplest solution is the most powerful

What if a safety boot could simply be taken apart at the end of its useful life for high-quality recycling?

How a reversible adhesive can make safety footwear more recyclable

What if a safety boot could be completely and easily dismantled at the end of its life? So that the various materials could be reused? Over the next three years, EMMA, together with knowledge and industry partners within the CircuTherm project, will investigate whether so-called ‘reversible glue’ can make this possible.

“When this idea was first presented to me, I was immediately enthusiastic,” says Elroy Bongers, Head of Innovation and Sustainability at EMMA. “The concept is very simple. That is precisely what makes it so powerful.”

EMMA is taking part in the three-year CircuTherm project, which is working on a thermoplastic ‘reversible glue’. Elroy: “This is a reversible adhesive that allows you to firmly bond shoe components and then separate them again at the end of their lifespan. Within the consortium, EMMA is collaborating with TNO, Eindhoven University of Technology, Maastricht University, Yparex B.V. and Hybrid Catalysis.

From bonding to separating

According to Elroy, the reversible principle is essential: “A safety shoe consists of different materials that are firmly bonded together. This is necessary during use, but poses a challenge at the end of its service life. For high-quality recycling, materials must be separated as much as possible.”

Smart heating in the right place

A key advantage of the technology lies in the way it heats. “In traditional production processes, you heat an entire shoe – the sole and the upper – in a sort of oven,” says Elroy. “With this technology, you only heat the nanoparticles in the adhesive bond. This generates heat exactly where it’s needed. The result is a fast, fully electric and energy-efficient process. With an efficiency of up to 90 per cent, less energy and raw materials are wasted, CO₂ emissions are reduced and new circular applications are created.”

“This is one of those rare projects where both sustainability and efficiency come out on top.”

A rare win-win

For EMMA, the strength lies in the combination of circularity and efficiency. “Many sustainability projects ultimately boil down to a trade-off between environmental impact and costs. This is one of those rare projects where both sides can benefit. You can save energy, speed up processes and make products more recyclable.”

And the wearer?

“They won’t notice a thing,” says Elroy. “Safety, comfort and quality always remain the top priority. Our aim is for users to experience the same quality, whilst reducing the environmental impact of products. In addition, this may create new opportunities for repair and extending the product’s lifespan.”

More than just technology

Although the technology has great potential, Elroy emphasises that it is not the complete solution. Within the CircuTherm project, EMMA is therefore primarily contributing practical expertise. “Researchers can come up with fantastic solutions, but ultimately it must also work in a factory and meet all the requirements we set for safety footwear.”

“Being able to take a shoe apart is just the first step,” he continues. “After all, you then also need a return stream, partners who process the materials, and ways to reuse them.”&” According to Elroy, CircuTherm is therefore an important piece of the jigsaw, but not the complete solution. “Circularity requires collaboration throughout the entire supply chain. That is why EMMA is developing several initiatives simultaneously.”

"Circularity requires collaboration throughout the entire supply chain."

Broader ambition

For EMMA, the project forms part of a broader vision. “Our dream is for EMMA to become the circular hub for safety footwear in Western Europe. Not just by manufacturing shoes, but also by recovering materials and reprocessing them. CircuTherm is helping us move closer to that future, step by step.”