Innovation: Welding uncoated paper with ultrasound

To reliably join uncoated paper, additional resources in the form of adhesives or staples have always been required. In the near future, paper will be affixed much more sustainably using ultrasound alone. What has so far been successfully confirmed under laboratory conditions is now to be established on an industrial scale for the first time. To this end, Herrmann Ultrasound will test the innovative process together with customers in its ultrasonic laboratories and, therefore, further optimise it.

„Previously, we needed at least a small amount of plastic in the material to ultrasonically seal paper - we can now do without this material entirely. This opens up completely new possibilities for the environmentally friendly design of packaging. This is a major milestone on the way to a functioning circular economy. We are delighted that, together with Syntegon, we have been able to create the framework conditions to make this innovation ready for series production.“

Thomas Herrmann, CEO at Herrmann Ultraschall

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Ultrasonic welding of paper works similarly to plastics but with one crucial difference: the material must be moistened before the welding process. The welding tool, the sonotrode, transmits ultrasonic vibrations to the paper, causing the fibres to separate at the point of contact between the layers of paper and join them together again. The frictional heat generated between the materials causes the applied moisture to evaporate during the process without damaging the paper. This creates a high-strength and visually perfect bond within a very short time.

„In the Herrmann Ultraschall Group, we have found a competent partner who will bring this promising technology to all packaging applications with fibre-based materials. The ultrasonic expertise of our partner will create the conditions for broad acceptance of the process on the market.“

Dr Johannes Rauschnabel, Head of Advance Development at Syntegon

The areas of application for ultrasonic welding of paper are diverse: from primary packaging such as fruit trays made of thin cardboard to secondary packaging in the form of paper bags. In addition to saving on joining agents, the main advantages for companies are low energy consumption, fast process times and extremely low wear on the welding tools. In addition, uncoated paper is much easier to recycle, which further improves the sustainability balance of packaging.

http://www.herrmannultraschall.com, http://www.syntegon.com