IN Brief:
- HolyGrail is testing digital watermarking and recycling routes for polypropylene snack packets.
- The project targets food-grade recycled polypropylene from flexible snack packaging.
- Flexible food packaging remains one of the hardest streams to recover into higher-value applications.
HolyGrail 2.0 technology is being applied to one of food packaging’s most difficult waste streams, with partners testing whether digitally watermarked crisp packets and snack wrappers can be sorted and recycled into new food packaging.
The project focuses on polypropylene flexible packaging, a material widely used for crisps, snacks, confectionery, and dry food products because it combines low weight, barrier performance, printability, sealability, and high-speed packing compatibility. Those characteristics have made polypropylene valuable on the production line, but the same structures have often been difficult to recover into higher-value recycled streams.
Digital watermarking gives packaging a machine-readable identity that can be detected during sorting. The watermark can carry information such as material type, packaging use, and food-contact status, allowing suitable packs to be separated from mixed household packaging waste. Better sorting is essential when the target is food packaging, because recycled food-contact materials require cleaner and more controlled feedstock streams than many lower-value recycled applications.
Snack packaging sits at the centre of a long-running trade-off. Crisps and similar products need protection from oxygen, moisture, grease, aroma loss, crushing, and seal failure. The packs must also run at high speed, support brand printing, survive distribution, and fit multipack systems. Flexible plastics have served those requirements efficiently, but their end-of-life route has lagged behind their production performance.
The regulatory squeeze on flexible food packaging has already been building through new pressure on recyclability, documentation, and material design. Multilayer structures, metallised films, inks, adhesives, coatings, and mixed polymer combinations can complicate recycling even when they deliver strong product protection. Snack manufacturers are now being asked to preserve shelf life while preparing for stricter circularity rules.
Digital watermarking does not remove the need for better pack design or stronger recycling infrastructure, but it addresses a decisive bottleneck: identification at scale. Conventional sorting systems can struggle with thin, printed, crumpled, or contaminated flexibles. If packaging can carry reliable data into the waste stream, sorting plants can generate more consistent feedstock for mechanical or advanced recycling routes.
The food-contact element raises the technical bar. A mixed flexible stream may contain packaging from food, personal care, household, and other uses, each with different contamination profiles. A system that can distinguish food packaging from non-food packaging improves the chance of producing recycled polypropylene suitable for demanding applications. Without that separation, recycled material is more likely to be downcycled into products with lower safety and performance requirements.
Commercial success will depend on more than the watermark. Collection systems have to capture the packs. Sorting facilities need compatible detection equipment. Recyclers need enough clean feedstock to justify investment. Converters need recycled material that can meet process and performance requirements. Brands need confidence that the resulting packs will satisfy safety, regulatory, and consumer expectations.
The EU Packaging and Packaging Waste Regulation is moving those questions closer to board-level packaging strategy. Recyclability, recycled content, material restrictions, and end-of-life data are becoming commercial requirements rather than voluntary sustainability goals. UK film collections and EPR fees will add further pressure as flexible packaging becomes more visible in cost and compliance systems.
The HolyGrail trial points to a systems-based route for a category that cannot easily abandon flexible plastics without risking food waste, product damage, or poor production efficiency. Polypropylene snack packets have been optimised for product protection and line performance over decades. Creating a circular route now requires machinery, data, sorting, recycling, conversion, and food-contact validation to align across the value chain.
If the approach can be proven at scale, the result would extend beyond crisp packets. Many dry food and confectionery formats face similar packaging pressures, and a reliable route for food-grade recycled polypropylene would widen the options available to pack designers. The immediate task is technical and operational: turn intelligent sorting from a promising concept into a repeatable industrial process.
