Austria-based flexible packaging manufacturer Constantia Flexibles, in collaboration with German thermal technology company watttron, has developed a new lid sealing system. 

The new system is capable of handling polypropylene (PP) and aluminium lids on PP cups within a single production line.  

The system builds on Constantia Flexibles’ PPCover, a mono-material PP lidding solution designed to meet recyclability standards. 

Traditional sealing machines typically heat the entire sealing head, which can cause issues such as material curling.  

The new system uses watttron’s ring-heating technology, applying heat only to the outer sealing ring in a targeted approach which reduces thermal stress and improves energy efficiency.

The system heats and cools at between 10°C and 20°C per second and maintains the set temperature within ±1°C.  

Lab-scale trials with PPCover showed consistent sealing performance for both PP and aluminium lids, demonstrating strong peel strength and internal pressure resistance.  

watttron CEO Marcus Stein noted: “We developed our ring-heating technology to deliver precise energy exactly where it’s needed — no more, no less.  

“That precision not only improves quality and flexibility, but also contributes meaningfully to energy efficiency in packaging lines.” 

Constantia Flexibles stated that the system provides operational advantages by eliminating the need for separate machines for different lid types, simplifying production processes and reducing equipment complexity.  

It also features 100% inspection capability to detect and remove defective cups in real time.  

Constantia Flexibles market product manager for die cut lids Claus Dworschak stated: “This is a strong one-fits-all solution in dairy lidding.  

“It simplifies operations and enhances quality — exactly what our customers need.” 

Constantia Flexibles employs 8,780 people across 37 sites in 18 countries.