Welded Loop: Dutch designers create shoes made from 100% TPU

A duo of Dutch designers have created footwear made entirely from TPU, a flexible and recyclable thermoplastic. By leveraging manufacturing processes like 3D printing, knitting and welding to craft the shoes, the designers were able to manipulate TPU in various ways and even eliminate the need for any adhesives. The footwear project, called Welded Loop, is not quite ready for commercialization, but it does demonstrate how a single material could be used to create wearable shoes, which could in turn facilitate recycling at the end of their life.

The Welded Loop project is spearheaded by Suzanne Oude Hengel and Joris de Groot, who have known each other and collaborated for years. Oude Hengel, who runs a textile design studio called Knit in Motion, and de Groot, who specializes in high-frequency welding (a technique that uses high-frequency electromagnetic waves to weld plastic materials), became interested in designing the mono-material shoe when they realized they could make textiles from 100% TPU yarn.

Conventionally manufactured shoes are typically made from many different materials, like rubber, plastics, textiles, leather and adhesives, which makes them challenging to recycle when they can no longer be worn. A mono-material material shoe made from a recyclable thermoplastic, however, could offer a significantly more sustainable footwear option.

“There is a lot of functionality to answer to in shoes, which is why you normally see so many different materials and glues,” said Oude Hengel in an interview with Dezeen. “Our challenge was to make a very clear and simple shoe using a single material,” added de Groot.

The Welded Loop project was first presented last month at Dutch Design Week in Eindhoven, though the project is still in its early stages. Currently, the shoe prototype is made by knitting TPU into a textile using a template. 3D printed eyelets are then welded to the textile, which is placed on a mold and thermoformed to create an upper. The soles are 3D printed separately—using a TPU filament—and then welded to the upper.

Going forward, the designers plan to use TPU yarn and 3D printing to create other mono-material products. Ultimately, the goal is to bring Welded Loop footwear to the commercial market. “There is so much potential that we haven’t researched yet,” added Oude Hengel. “We want to explore the full scope of what’s possible before we become too led by creating a product.”