Speaking at Anuga FoodTec, where Sidel showcased its ‘Stack & Pack’ technology for the first time, Eric Schaffner, international key account manager, Sidel, explained how a deep concave indentation in the base of a square-shaped 500ml PET bottle – created via Sidel’s patented ‘stroke base’ technology, allows the neck of one bottle to fit into the base of another above.
Packaging giant Sidel (part of the Tetra Laval group with Tetra Pak) said that 500ml and 1 litre bottles were available, and were suited for filling with sensitive products such as juices, liquid dairy and milk. The firm is now ready to conduct field tests at customers’ plants, ahead of the first product launches.
Asked when the first products using Stack & Pack could appear, Schaffner said:“We need to complete some tests but I can imagine that – when a customer buys into the concept – it is something you could easily see in 2013. I don’t really see why it should take longer.”
Crushed bottle necks
Potential advantages for beverage producers and co-packers include the ability to dispense with carton interlayers and optimise storage space – and fuel costs, given that fewer pallets are required to transport the same product volume by road – and avoid crushed bottle necks.
Retailers would also benefit from greater bottle numbers on less restocking of shelves, as well as a more attractive look to the fixture, Sidel claimed, while bottles were easy for customers to ‘grab and pour’ and required minimum at home storage space.
Explaining the technology behind the concave indentation, Schaffner said: “On bigger bottles you can do it just by blowing – here you need a special step in the blowing stage to achieve that effect with the bottle. With bigger bottles you just need a mold where you already have the shape so you have the space for the cap. With a smaller bottle this is not possible.
“Without disclosing any technology, we apply a patented step during the pre-form blowing process so that we form the space in the bottle – it’s not standard blowing with the mold, which doesn’t bring this benefit,” he added.
“The concept as such where you can stack a bottle, a big bottle, is on the market already, but a bottle of the size of 500ml, 1 litre, did not exist as such. On the blowing side, we are set. But we still want to work on the palletisation – and have already done some tests – it works, but we want to refine it.”
More bottles on pallet
Ten layers of 500ml bottles (rather than the usual six) can be packed onto a standard European pallet, and Sidel said that this increased the number of square bottles on the pallet by 40% (2,160 units versus 1,296); Schaffner estimated a new figure of circa. 1,800 for round bottles.
Stroke-base technology also cuts blowing pressure by up to 10 bars during production, Sidel said, while the stackable bottles could be produced in different shapes (including round bottles) and sizes; the surface area of square bottles offered strong branding potential.
But although more square bottles could be fitted on a pallet, Schaffner noted that there was a PET weight premium trade off vis-à-vis round bottles.“What you gain on logistics thanks to packing and stackability will be upset slightly by the additional weight,” he said.
“Weight is a big issue in this industry regarding total ownership cost, and it will increase. At the base of each issue we have petrol. Logistics costs more and more, but weight does also.”