Sukano has announced the development of an additive masterbatch package designed to enable the production of fully recyclable PET closures. The solution targets a persistent limitation in PET bottle recycling, namely the inability to recycle caps made from different polymers together with the bottle body in a single stream. By allowing monomaterial PET or rPET caps to be processed alongside clear PET bottles, the technology is intended to support bottle-to-bottle circularity and increase the overall availability of bottle-grade recycled PET without requiring changes to existing processing equipment.
From multimaterial caps to monomaterial PET solutions
PET bottles are currently the most widely recycled plastic packaging format and constitute the largest global source of high-quality recycled PET. However, the closures have historically fallen outside this circular system. Caps are typically produced from polypropylene or high-density polyethylene. As these materials differ from the PET bottle body, they must be separated during the recycling process to avoid contamination of the PET stream, which has limited full bottle-to-bottle recyclability.
The newly developed additive package allows manufacturers to produce monomaterial PET or rPET caps that can be recycled together with the bottle without additional separation. This approach eliminates the multimaterial constraint and is intended to streamline the recycling process. Given that caps can represent up to 10% of the total bottle weight, integrating closures into the same recycling loop can unlock thousands of tons of additional bottle-grade PET for circular reuse.
The additive package is suitable for both thermoforming and injection molding, which enables producers to convert to monomaterial bottle and closure solutions within their current processing infrastructure. This compatibility is positioned to facilitate adoption by allowing a transition to PET closures without requiring new equipment or major process modifications.
Recyclability testing under TCEP and EPBP protocols
To verify performance in recycling conditions, Sukano conducted in-house tests in its recyclability laboratory in line with the Tray Circularity Evaluation Platform and European PET Bottle Platform protocols. Each additive in the formulation was evaluated at inclusion levels significantly above typical use rates. While the additive is generally used at concentrations of 1–2%, internal testing was carried out at dosages of up to 5% and with up to 50% recycled content.
Testing under the TCEP protocol for thermoforming applications and EPBP protocols for PET closures indicated no impact on the key optical and molecular parameters of the recycled PET stream. According to the company, there was no negative effect on color, haze or intrinsic viscosity, which are among the central technical criteria for acceptance of materials into the clear PET bottle recycling stream.
In line with the company’s stated design for circularity principles, potential accumulation of the additive over multiple recycling cycles was also assessed. The tests confirmed that repeated recycling of materials containing the additive did not disrupt the existing recycling process for clear PET bottles, supporting its suitability for use in closed-loop applications.
Formulation designed for food contact safety
The additive package was formulated with an explicit focus on safety, with the composition engineered to avoid substances of concern by design. To further evaluate the safety profile, a screening of non-intentionally added substances was carried out by an independent laboratory. The screening applied generally recognized scientific methods and the findings were assessed using internationally accepted risk assessment approaches.
This evaluation was intended to identify and manage any potential consumer safety risks associated with the migration of such substances from packaging into food. On this basis, the company states that the additive system complies with stringent food safety and packaging regulations in markets worldwide, making it suitable for use in food-contact PET closure applications that are intended to enter circular recycling streams together with clear PET bottles.
