Measuring blood sugar levels on the skin, packaging with an integrated time-temperature indicator or a greeting card that plays music - electronic components are needed for all of these. The electronics consist of printed circuit boards (PCBs) with elements such as sensors, chips, capacitors and resistors. PCBs are usually made of a glass-fibre polymer composite material with copper-based circuits and some other materials.
Of the twelve million tons of electronic waste generated in Europe each year, only 42 per cent is properly collected and recycled (source: World Economic Forum), and worldwide the figure is only 17 per cent (source: Global E-Waste Monitor 2020). The EU project "CircEl-Paper" is therefore pursuing the goal of producing functional printed circuit boards based on paper technology so that the electronics can be disposed of and even recycled at the end of their life in the conventional paper recycling process. This could reduce recycling costs and facilitate the recovery of valuable materials.
Research into new materials and their recyclability
At the MATERIALS Institute research is being conducted into the development of suitable materials, because the cellulose-based substrate that is to replace conventional printed circuit boards materials must meet the demands of the electronics industry. "We are developing additives, i.e. auxiliary materials, to make the paper stable and compatible with common integration processes, and we are developing inks for printing conductive tracks as well as passive components such as capacitors, resistors and insulators," reports Oliver Werzer, project manager at the institute. "We are also looking at scalable processes that allow these novel materials to be applied to a printed circuit board made of paper and enable rapid application in industry. The use of resource-saving and environmentally compatible materials and processes has the highest priority: the materials used should increase the separation of components and their recyclability, and bio-based alternatives are being evaluated."
The researchers at the LIFE Institute are taking a close look at the recyclability of the newly developed materials. Evaluations performed on the overall sustainability of the manufacturing processes and the recycling of the materials used by means of life cycle analyses (LCA) - from the "cradle to the grave". Sara Carniello who is in charge of the project, says: "Detailed LCA studies and the evaluation of recyclability are not standard for such complex technologies. They require in-depth know-how about the materials and technologies as well as a further development of the LCA methodology, especially for the assessment of the circularity. Circular economy and sustainability of the different approaches developed in the project will be assessed at an early stage and taken into account by the consortium in the selection and further development of the technological options."
The potential applications of paper-based PCB technology will be demonstrated using three use cases from the fields of medicine, logistics and consumer electronics: Using a sensor to measure blood sugar levels on the skin, packaging with an integrated time-temperature indicator and greeting cards that play music.
LIFE and MATERIALS are part of an international consortium that has been working on the CircEl-Paper project since September 2022 and covers the entire value chain.