conference report | Thin wall packaging
Sustainability options Weight reduction is also an element within Danone’s packaging sustainability strategy, which aims to decrease its carbon emissions per pack by 30%. Danone packaging and environment manager Dr Philippe Diercxsens detailed the strides the company has made in reducing the weight of PET preforms and bottles used in its Waters division. However, he also emphasised that its weight reduction initiatives are accompanied by strategies such as use of more recycled resin, designing containers for easier recycling, and the exploitation of new bio-based momomers and polymers. Diercxsens cited the example of its 1.5 litre Evian
Strategic directionS in thin wall packaging marketS Source: ami
Nitrogen gas co-injection during tub production allows a product weight reduction up to 7%
Schematic Showing the VeriplaSt Slim foamed moulding proceSS Source: uniliver
plasticising to create a lightly foamed article. The resulting 500g tubs weigh 14.3g – a reduction of close to 7% over a fully compact equivalent – while meeting the company’s 350N top-load requirement. Dreux said the original project brief set a series of
targets - the parts had to save weight and meet its cost requirements while presenting no visible “difference” to the consumer or requiring changes to the company’s supply chain. However, he said the company has found the new technology allows it to explore new functional- ity in the packaging design. “Instead of making no difference for the consumer we could bring extra value,” he said. Citing the example of the Planta brand of spreads sold in Belgium, Dreux said the SLIM technology is being used in conjunction with IML techniques to create visible and tactile effects on the surface of the tub. The process, which the company said is being patented, uses a special varnish applied to the reverse face of the label which enables some of the dissolved gas to be retained in the polymer to create a selectively applied embossed effect in the final part after de-moulding. The resulting raised surface provides an enhanced visual and sensory effect that Dreux says could be exploited to increase shelf appeal. However, it could also be used to provide braille markings or to improve insulation performance, said Dreux.
48 INJECTION WORLD | April 2012
water bottle, which has been reduced from 42g in 1995 to 28.6g in 2010, alongside the introduction of 25% recycled PET content. Last year, the company also introduced new versions of its single serve Evian bottles – the 0.33l bottle went from 12.8g to 11.8g and the 500ml version from 15.8g to 14.3g. The challenge in further reducing weight is to maintain satisfactory performance on the bottle filling line and in the hands of the consumer. Diercxsens described these as “critical” requirements. One of the key areas of interest for producers of injection moulded thin wall packaging is barrier performance, allowing plastics packs to be produced that provide oxygen barrier levels required for extended life applications. With a production capacity of 24,000 tonnes a year at its European operation at Antwerp in Belgium, Eval – a subsidiary of Kuraray of Japan – claims to be Europe’s leading manufacturerr of EVOH barrier resin. At the conference, Didier Houssier, business development manager for Eval Europe, presented the findings of a study the company carried out to determine which processing technologies were best suited for specific barrier packaging tasks. Houssier explained that the molar fraction of ethylene
in the EVOH copolymer determines its performance and processibility – higher ethylene content copolymers process better but offer lower barrier performance. This means that the barrier performance of a package will be influenced by copolymer selection as well as the layer thickness, and both will be in some way impacted by processing technology.
Packaging comparisions The Eval study took samples of PP/EVOH/PP packaging from the marketplace – including laminated and coextruded thermoformed parts and IML and multilayer injection mouldings - preconditioned them identically,
then measured O2 GTR (oxygen gas transmission rate). Results were standardised for package surface area to allow a comparison to be made by thickness of the
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