According to Covestro, the manufacture of a shoe requires a multitude of work steps, some of which are carried out by hand. This makes production time-consuming and expensive. In the finished product, various materials are sewn together and glued together, so that it is virtually impossible to recycle them by type at the end of their useful life.

Shoes can be made from only two parts using 3D printing – the sole and the uppers. To produce both parts, Covestro has developed a TPU so that the shoe can be completely recycled at the end of its useful life. (Source: Covestro)

Using 3D printing, shoes could be made from only two parts – upper and sole. Covestro has developed a material that enables automated production at lower cost and complete recyclability of the finished shoe. The company presented these and other developments of its additive manufacturing programme at the Formnext 2019 in Frankfurt am Main, Germany.

A powder and a filament, both based on thermoplastic polyurethane (TPU), proved to be the material of choice for meeting all the above requirements. The plastic offers high rebound and abrasion resistance and is therefore ideally suited for the production of both shoe parts, said Covestro. In addition, the shoe can later be recycled in a single step, including the polyurethane adhesive used for production – an important milestone towards recycling. Old shoes are thus turned into filaments for new shoes.

Covestro has also launched Addigy, its new brand for custom 3D printing. Officially launched at Formnext 2019, Addigy focuses on providing material solutions used in industrial 3D printing production. These include polycarbonates, thermoplastic polyurethanes and polyurethane-based resins.

www.covestro.com