Constantia Flexibles and Watttron have developed a new approach to lid sealing that enables both polypropylene (PP) and aluminium lids to be sealed on PP cups using a single system.
The initiative builds on Constantia Flexibles’ PPCover, a mono-material PP lidding solution. Integrating it into existing sealing machines presented a technical challenge: ensuring consistent, high-quality seals across different lid materials without introducing inefficiencies or material deformation.
Traditional sealing systems typically heat the entire sealing head, which can lead to issues such as curling due to excess heat exposure. Although not widespread, this risk prompted Constantia Flexibles to explore more precise and adaptable sealing methods to ensure long-term reliability and compatibility.
Watttron’s ring-heating technology applies heat only to the outer sealing ring. This targeted method reduces thermal stress on the lid material and aims to significantly improve energy efficiency.
The company says its system heats and cools rapidly—typically at a rate of 10 to 20 °C per second—and maintains the set temperature with a high degree of accuracy (±1 °C).
According to Constantia, these features not only support consistent sealing performance but also allow the system to be safely powered down during production stops, contributing to energy savings of up to 50% compared to conventional sealing methods.
Marcus Stein, CEO of watttron, says: “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.”
The companies hope that their new product will eliminate the need for separate machines or setups for different lid materials, simplify production processes, and reduce equipment complexity.
The system also integrates with 100% inspection capabilities, in a bid to enable the real-time detection and removal of defective cups.
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