RPC Cobelplast has achieved a significant breakthrough in sheet technology by co-extruding a two-colour striped barrier sheet for Ferrero’s famous Nutella chocolate spread portion pack.

The distinctive appearance of the portion pack – which mimics the shape of the regular Nutella jar – had previously been thermoformed using two-colour printed barrier sheet to achieve the design’s white ‘cap’ and brown ‘base’ effect.

The distinctive appearance of the portion pack – which mimics the shape of the regular Nutella jar – had previously been thermoformed using two-colour printed barrier sheet to achieve the design’s white ‘cap’ and brown ‘base’ effect. Ferrero expressed a desire to enhance the pack appearance by sharpening the contrast between the colours, whilst maintaining the existing jar-shaped design. It was agreed that the logical solution was to combine two colours of the barrier material at the co-extrusion stage, thus avoiding the need for printing afterwards. This presented RPC Cobelplast’s Technical Manager, Tino Van Iseghem, and his team with a formidable challenge, as the sheet needed to be co-extruded in a striped pattern. Although striped monolayer sheet has existed for decades, the technique had never been successfully implemented on barrier sheet. RPC Cobelplast, working in close collaboration with its equipment supplier, set up a project team to devise a solution. The technical challenge was to combine the existing stripe bar die technology with the barrier feedbloc technology, in such a way that the configuration of the flow channels in the feedbloc minimises the number of used extruders. As the procedure involved major adjustments to one of RPC Cobelplast’s coextrusion lines, all technical, financial and marketing implications were carefully studied, and the progress evaluated at regular intervals. The success of the project has extended the range of barrier sheet solutions that RPC Cobelplast can offer to its customers.