3D printing on textile fabrics can be used to create composites with position-dependent mechanical, water-resistant, magnetic or other properties. An important prerequisite to use such composites technologically or for design purposes is a sufficient adhesion between both materials. While previous studies revealed that soft, elastic printing polymers were advantageous to prepare connections with a high adhesion, not much research has been performed yet on the dependence of the adhesion on textile fabric structure, heat post-treatment, and the influence of washing, which is necessary for most applications of such composites. Here we investigate composites from thermoplastic polyurethane (TPU) 3D-printed on two different woven cotton fabrics. Besides the expected strong correlation of the adhesion with the distance between nozzle and printing bed, we find a higher adhesion on the thinner fabric and an increase in the adhesion after one washing cycle.

3D printing belongs to the emerging technologies of our time. While it enables producing new structures and makes individualized products affordable, 3D printed objects still suffer from low production speed and often insufficient mechanical properties. Both these problems can be tackled by combining 3D printing with substrates prepared by conventional technologies, e.g. textile fabrics. In this case, the adhesion between both partners is most challenging and defines for which possible applications such composites are suitable. Here, we report on a new approach to increase the adhesion between 3D printed materials and warp knitted fabrics, showing that in some cases a thermal after-treatment, in the simplest case performed by ironing, is able to significantly increase the adhesion between both materials.