The recyclability of PET bottles is determined not only at the recycler but throughout the entire value chain: From preform manufacturers to beverage fillers to retailers, the right decisions must be made early on. The development of specialized raw materials, suitable labels, and adapted adhesives determines whether a bottle can be reused for high-quality applications like food packaging at the end of its life cycle.
Dispersible adhesives make a decisive contribution here. They make PET bottles truly recycling-friendly and ready to meet the requirements of the new EU regulation. After all, anyone aiming to achieve the ambitious PPWR targets needs solutions that not only stick reliably – but also let go at the right moment.
In specialized recycling plants, collected PET bottles are first shredded, and the resulting flakes are washed in hot water baths. While lightweight label remnants float and can be skimmed off, many conventional adhesives remain stuck to the flakes. Even in the standard process using hot caustic soda, which removes label material, adhesive residues, and other contaminants from PET, conventional hot melts often only partially detach. Typical removal rates range between 12% and 30%.
The consequences of these residues are severe: They cause cloudiness and yellowing, reducing the optical quality of the reprocessed PET material. Even more problematic is when barrier properties are compromised by contaminated flakes. This is especially critical for food packaging, as PET bottles – usually thin-walled for resource efficiency – are particularly vulnerable to weakened barrier performance. Such impairment can allow oxygen or other contaminants to penetrate, jeopardizing food safety. For PET bottles, contaminated flakes are therefore no longer suitable – at best, they can hope for a new life as a sweater, flowerpot, or strapping tape.
Modern adhesives face high demands: They must not only ensure PET truly stays in the loop but also be compatible with common labeling techniques. One solution is dispersible hot melts – adhesives that almost completely dissolve or transform into an easily removable form in hot caustic soda. For example, Henkel Adhesive Technologies’ TECHNOMELT EM 335 RE can be removed up to 98% residue-free. Specifically developed for PET labeling, its dispersibility in hot caustic soda ensures adhesive residues are separated from the material stream along with the label material. This supports the production of ultra-pure PET flakes suitable for new food packaging.
Beyond recyclability, the solution offers additional benefits: The hot melt works for both paper and plastic labels and can be processed on lines running up to 40,000 bottles per hour. Its low application temperature of 110–140 °C protects equipment and reduces energy consumption. Thanks to its mineral oil-free formulation and food compliance, it is also suitable for sensitive applications. Handling is further simplified by practical packaging in so-called X-tra Chubbs, which enable precise and clean adhesive dosing and contribute to packaging reduction through complete film dissolution.
