Tamper evident closure 'another way to meet customer needs' - company
The linerless plug is used to seal juices, isotonics, dairy, energy drinks, milk, vitamin waters, drinkable yogurt and teas.
The Steri-Shield closure can be made in 38-43mm for ESL and aseptic beverage packages and was launched in a taller profile than non-TE after the success of earlier models, said Portola.
It is compression moulded using high-density polyethylene (HDPE) for a lightweight design which can withstand an aseptic sterilisation environment of up to 140 degrees.
The firm said offering this alternative “gives brand owners another way to meet consumer needs.”
Internal testing
Commercialisation is being backed by shelf-life testing protocols that were developed internally to predict the performance of the plug closure over time and computer modeling was used to project shelf life to ensure the closure met expectations.
Roy Robinson, vice president of business development at Portola Packaging, told FoodProductionDaily.com there had been a positive market response to their closures.
“Most closures we sell are to the dairy industry where [a] 20 day shelf life is common. The extended shelf life segment requires 90 to 120 days. And then the aseptic market is about six months.”
Last year Portola announced it could produce closures suitable for low and high acid aseptic applications and claims to be one of the first North American manufacturers to commercially produce linerless closures which meet rigorous market demands.
Past methods
Previously, closures with thermoplastic elastomer (TPE) or foil liners had been used to achieve seal integrity for both low and high acid beverages.
The new plug design helps minimise package cost by eliminating the liners and contributes to source material reduction, said Portola.
When asked why the firm had moved away from TPE or foil liners, Robinson added: “Bottle seal integrity through sterilisation of closures and bottles and distribution demandsconsumer convenience – reduction of hard to open complaints.”
