Adhesives used under labels remain a barrier to closed-loop recycling of PET bottles, despite high collection rates across Europe, according to material suppliers working on dispersible hot-melt formulations designed to separate cleanly during recycling.
PET bottles account for around 70 per cent of global PET consumption and are a key focus of the EU Packaging & Packaging Waste Regulation (PPWR), which requires single-use PET bottles to contain at least 25 per cent recycled content from 2025, rising to 30 per cent for all plastic bottles by 2030.
While more than 60 per cent of PET bottles are collected in Europe, recycling outcomes depend on whether bottle components, including labels and adhesives, can be removed without contaminating the PET flake stream. Adhesive residues left on flakes can make recycled PET unsuitable for food-contact applications.
In standard recycling processes, PET bottles are shredded into flakes and washed in hot water or hot caustic soda baths. Label materials typically detach and float, but conventional hot-melt adhesives often remain bonded to PET flakes. Industry data cited by Henkel Adhesive Technologies puts removal rates for conventional adhesives at between 12 per cent and 30 per cent.
Residual adhesive contamination can cause cloudiness and yellowing in recycled PET and may compromise barrier properties. This is particularly problematic for thin-walled PET bottles used in food packaging, where reduced barrier performance can affect product protection. As a result, contaminated flakes are typically diverted into non-food applications.
To address this, adhesive suppliers are developing dispersible hot-melt adhesives designed to dissolve or disintegrate in hot caustic soda, allowing separation from PET during washing. Henkel Adhesive Technologies points to its TechnoMelt EM 335 RE as an example, stating that it can be removed by up to 98 per cent under recycling conditions.
The company says the adhesive is compatible with both paper and plastic labels and can be processed on bottling lines running at up to 40,000 bottles per hour. It is applied at temperatures between 110°C and 140°C, which Henkel says can reduce energy use and equipment stress. The formulation is mineral oil-free and food compliant, according to the company.
Under the PPWR, PET bottles must be both recyclable and increasingly made from recycled material, placing pressure on the entire packaging value chain. From preform manufacture to labelling and filling, material choices determine whether bottles can be recycled back into food-grade applications.
Dispersible adhesives are positioned by suppliers as one element required to improve material separation and support bottle-to-bottle recycling as regulatory requirements tighten across Europe.
