Labels for Recycled PET Bottles: Preserving Clarity, Adhesive Compatibility, and Sortability
Recycled PET (rPET) bottles are progressively replacing virgin PET in the beverage, cosmetics, and personal care industries, particularly in markets with mandatory recycled content regulations such as the EU (SUP Directive requires 25% rPET by 2025 and 30% by 2030). However, labels for recycled PET bottles present distinct technical requirements compared to those for virgin PET bottles. The rPET surface can be less uniform, with lower optical clarity, and notably, the surface energy may vary depending on the source of recycled material and the bottle manufacturing process.
Three key factors when choosing labels for recycled PET bottles
1. Optical clarity: rPET generally has lower clarity than virgin PET, especially when the recycled material comes from colored or contaminated bottles. If the brand wants to maintain the ‘no-label look’ effect, it’s essential to choose an ultra-clear thin film label and test it directly on the actual rPET bottle. A clear label that looks perfect on virgin PET may reveal visible edges on rPET bottles due to the difference in clarity.
2. Adhesive and Surface Energy: rPET surfaces can exhibit lower surface energy than virgin PET, especially if the bottles are treated with scratch-resistant coatings or barrier layers. Adhesive selection should be based on actual testing conducted on the specific production batch of bottles, rather than relying solely on catalog specifications. Additionally, if rPET bottles will pass through washing lines and be reused, wash-off adhesive is mandatory.
3. Sortability in the recycling stream: The ideal label for rPET bottles should be made from the same PET material family and have a density lighter than water so it floats in the wash tank, easily separating from sunken PET bottle flakes. If PET labels cannot be used, PP or PE labels must feature wash-off adhesive to ensure complete separation during the recycling process and prevent contamination of the rPET stream.
Hirich’s Recommendations for Recycled PET Bottle Labels
Labels for recycled PET bottles should be designed following the ‘Design for Recycling’ principle: PET labels with wash-off adhesive are the optimal combination. If aesthetic requirements necessitate the use of a different film label (PP, PE), wash-off adhesive must at minimum be used, and the label must feature colors/density that allow optical sensors in recycling plants to sort it effectively. Hirich advises businesses from label structure selection and testing on actual rPET bottles to recyclability confirmation, ensuring that recycled PET bottles are truly recycled once more, closing the circular loop.
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