German bottling equipment maker Krones (Neutraubling; www.krones.com) and Austrian plastic packaging manufacturer Alpla (Hard; www.alpla.com) have formed a joint research project to explore the development of returnable PET containers for sensitive extended shelf life (ESL) products such as juice and milk. The main application for returnable PET containers has been carbonated soft drinks and water.

Tests to develop washing technology and analyse the interaction of different bottle designs with thermal, chemical and mechanical cleaning processes took place at Krones’ development plant for washing technology in Flensburg / Germany. Particular attention to the container-cleaning process ensured a high level of microbiological safety and a high number of container-use cycles while cleaning at lower temperatures, of around 60° Celsius.

Material and process parameters underwent a comprehensive scientific evaluation in the first phase. Based on the findings, Krones and Alpla developed a returnable PET container for ESL products such as milk and juice. A 38 mm bottle neck is an option for the container design. Preparations for a field test of the bottle is underway.