The TPU is the substrate for the printed copper circuits that are arranged in a meandering pattern and can be bent and stretched. At the center of the development is an electronic system that is responsive to movements without losing its functionality.
Covestro noted that what makes the product special is that light-emitting diodes are not positioned on a panel or strip, but on a piece of soft fabric. The LEDs can also perform key functions such as protecting pedestrians and cyclists against accidents.
Covestro’s smart circuits are manufactured using an efficient, multistage process. First, copper films are laminated onto the polyurethane films. The printed circuits are produced in a subsequent structuring operation featuring strong adhesion. The coated films are then shaped as required using conventional thermoforming.
“The films are resistant to standard etching and imaging processes,” said Covestro film expert Wolfgang Stenbeck. “Formable electronic systems can also be directly laminated onto textiles, as in the case of the luminous dress.”
The production technology was developed as part of various projects funded by the European Commission. The objective is to produce 2.5-dimensional electronic circuits cost-effectively using conventional forming processes. The freely formed components can be integrated seamlessly into energy-efficient electronic components. They can be processed using standard PCB industry equipment and are also suitable for applications with higher currents or voltages.
The smart circuits meet a range of customer needs and applications in a variety of industries. Compared with conventional electronic components, they offer greater design freedom and reliability while enabling more sustainable products due to the reduced use of materials.
The technology opens up an extremely wide range of options for smart textiles alone. Besides fashion items such as the luminous dress, freely formable electronic systems are already in use in underwear, where they monitor heart rate and breathing. They assist patients with therapy and help athletes monitor their training.
In consumer electronics, smart circuits are supporting the trend toward increased miniaturization of components, as they can be incorporated directly into the outer shell of products.
With 2015 sales of 12.1 billion euros, or $13.5 billion at current exchange, Covestro is among the world’s largest polymer companies. The main segments served are the automotive, electrical and electronics, construction and the sports and leisure industries, including fibers and films used in textile production. Covestro, formerly Bayer MaterialScience, has 30 production sites around the world.