THERMOFORMING | MATERIALS
More pressing matters: latest in thermoforming
Advances in thermoforming include a PET grade that allows hot filling – even with the inclusion of recyclate – and several ways to boost the use of polypropylene in packaging
At the Thin Wall Packaging conference in Germany last year – organised by AMI – delegates learnt some potential advantages of polypropylene and polyester thermoformed packaging. Jivan Ibrahim, business development manager
of Perstorp in Sweden, told delegates how recyclable hot fill packaging can be achieved using a range of its materials. These include its Akestra thermoplastic polyester, Holtac PVC co-stabiliser and a number of polyols for use as antioxidants, UV stabilisers and processing aids. Benefits of PET in this area include energy
efficiency and circularity – with several advances in PET recycling such as advanced sorting techniques and new ways of cleaning and decontaminating the material. He said that a key benefit of its new Akestra
grade compared to standard PET is that it has hotfilling capability – where standard PET does not. He cited the example of a three-layer thermofor- med container with a middle layer of rPET and outer layers of Akestra. It can contain up to 80% recyclate and is heat-resistant at 85-90C. Sheet used to make the container can use existing extrusion techniques. “It has tunable heat resistance regardless of PCR
content,” said Ibrahim. Here, he said PCR content has been varied
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between 30% and 90%, leading to a material with a maximum heat resistance of 75-95C. He also cited possible carbon footprint reduc- tion compared to polystyrene. While 100,000 tonnes of PS packaging would emit around 365,000 tonnes of CO2, he said Akestra with 30% PCR would cut this by 24%, while Akestra with 80% PCR would reduce it by 56%. “This is a flexible solution to tune heat resistance performance based on PET while keeping transpar- ency and rigidity benefits,” he said.
Mono material Andreas Goeldel, commercial technology director at Grupa Azoty Polyolefins in Poland, said there are many innovative applications of polypropylene (PP) in thin wall packaging. He pointed to the ability to make mono-material
packaging using PP – citing the example of an all-PP takeaway coffee cup. Ordinarily, he said, this might comprise a cardboard sleeve, cardboard body – with polyethylene (PE) liner, and polystyrene (PS) lid. “This makes things easier to separate and select during the recycling process,” he said. Similarly, a food container needs a coating in
order to protect the contents – unlike, say, a cardboard tray, which may require this for protec- tion against wet or oily contents.
� March 2024 | FILM & SHEET EXTRUSION 21
Main image: Perstorp’s new Akestra grade enables hotfilling capability
IMAGE: PERSTORP
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