Students of food packaging technology at Hannover University of Applied Sciences and Arts have developed completely recyclable yoghurt pots. They consist of only one material and are unprinted. With their invention, the students are applying for the Special Packaging Award of the German Sustainability Award.
Who separates the yoghurt lid from the cup/pot completely? The majority of consumers do not do this and thus – unconsciously – do not act ecologically. Yoghurt pots are made of plastic, but the lids are made of aluminium. If the two materials are not strictly separated, the scanner of a waste disposal plant cannot identify them clearly. Then the yoghurt pot would not be recycled or sorted out – or the aluminium would be thrown in together with the plastics.
As human habits cannot be changed overnight, there must be a different way of solving the “separation problem”, said eight students of food packaging technology in the Faculty of Mechanical Engineering and Bioprocess Engineering at Hanover University of Applied Sciences and Arts. Under the direction of Professor Dr. Rainer Brandt, they set out on a search for alternative pot shapes. The result is a yoghurt pot made entirely of thermoformed polypropylene, reports graduate engineer Sylvia Knebelsberger, team leader in food packaging technology. The conventional aluminium plate, which normally has to be separated from the pot so that the plastic can be assigned to a recycling stream, is replaced by Biaxially Oriented PolyPropylene film (BOPP film). “The lid no longer has to be removed. The cup/pot can be recycled completely,” says Knebelsberger. The oxygen barrier is therefore insignificantly lower than that of a PP pot with an aluminium plate, but higher than that of its PolyStyrene (PS) counterpart.
Lid detaches automatically when pot is opened
A further function of the aluminium plate, protection against light on the refrigerated shop shelf, is guaranteed by a lid made of solid cardboard, which is attached mechanically to the rim of the pot. “Here, too, there is no need for active separation by the consumer; the lid becomes detached automatically when the pot is opened and is thus separated. In addition, the tray is designed in such a way as to prevent light entering from the side,” explains Knebelsberger. A further ecological advantage is that the lidding film is unprinted. “This fact significantly increases the recyclability of the pot compared with printed plastic”.
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The Hanover-based young researchers are convinced that the cup/pot could be marketable. That is why they have submitted their invention for the Special Packaging Award of the German Sustainability Award. In cooperation with the REWE Group, the Special Award honours market-ready concepts and exemplary ideas that “reduce, optimise or avoid packaging, remain affordable in the mass market, and meet consumer needs for hygiene, information and convenience as far as possible”.
Knebelsberger adds that the pot could also be suitable for other dairy products. However, the students had only used the oxygen barrier of yoghurt as a basis for calculations. Nor was there any test phase during storage. And finally, it would have to be checked whether conventional packaging machines could easily destack the alternative lid. Since packaging also carries advertising messages, the students came up with a marketing idea for the unprinted pot. Their cup/pot is called “cuPP” – a play on words “cup/pot” and on spelling “see you PP”. “Thus the ‘cuPP’ is initially intended as an impulse for a closed-loop system of PP pots and could in the long term contribute to the large-scale production of food packaging from recycled material, i.e. ‘see you PP’,” write the young researchers.