Steri-Shield linerless plug closure technology

The Steri-Shield linerless plug closure technology is suitable for both low- and high-acid aseptic beverage packages.

Aseptic applications have traditionally used closures with thermoplastic elastomer (TPE) or foil liners to achieve seal integrity for both low- and high-acid beverages. By eliminating the liners, the plug design helps minimise package cost and contributes to material source reduction.

The aseptic linerless plug closures are compression moulded using a resin blend which includes high-density polyethylene. The end result is a lightweight closure which does not fail (stress crack, back-off, etc) during the sterilisation and/or distribution process. Additionally, the structure can withstand an aseptic sterilisation environment of up to 60°C.

The plug is also easier for consumers to open because there is no liner to negatively impact torque. The commercialisation is being backed by shelf-life testing protocols that Portola developed internally to predict the performance of the plug closure over time. Computer modelling was used to accurately project shelf life and other performance attributes to make sure that the closure would meet aseptic drink performance expectations.

The plug closures can be made in a variety of sizes ranging from 38 to 43 mm, with or without a tamper-evident band and is suited for a wide range of aseptically filled beverages including juices, isotonics, dairy, energy drinks, milk, vitamin waters, drinkable yoghurt, teas and others.