MATERIALS | THIN-WALL PACKAGING
Right: ICPG says its XPP product can replace PS in applications such as
thin-walled thermoformed containers
introduced by flow-controlled gas dosing of carbon dioxide or nitrogen. It requires efficient internal cooling, exact tempera- ture stabilisation and perfect melt homogeneity, he said. It has been applied to a number of structures, including both PS and PET trays and PP cups. The foamed PET trays – 18% lighter than their conven- tional equivalents – maintained the top load strength of a non-foamed tray, for instance. PP cups could be made 7% lighter – while also seeing a 65% increase in top loading strength.
Circular performance Sebastian Heitkamp, global business segment manager at BASF Switzerland, explained how the company’s IrgaCycle additives can help to raise the performance of polymers for packaging applications. IrgaCycle helps overcome many of the typical
problems of using recyclate, including reduced mechanical and thermal performance, gel forma- tion and lower processability. Its IrgaCycle PS 030G and 031G grades, for instance, are aimed at the flexible packaging and agricultural film markets. As an example, PS 030G was used at a 0.2% loading in rLDPE – and managed to reduce gel formation in cast packaging film. In addition, its IrgaClear XT is a clarifier that helps to raise recyclability, organoleptic qualities and processability, he said. It works at addition levels of 120-200ppm.
Clear advantage Similarly, John Mara, technical and marketing manager of Amfine Chemical, said that clarifiers help boost the transparency and clarity of PP. The main applications of thin wall packaging are for food containers such as cups and trays, he said – offering high productivity, low cost, light weight and ease of use. “There has been an increase in demand for home delivery and takeout due to the COVID-19 pandemic,” he said. “There is also a trend towards thinner packaging from the perspective of re- source saving.” By accelerating the crystallisation of PP, clarifiers can help to boost transparency and clarity and raise mechanical performance, he said. It is typically paired with either thermoforming or injection moulding for producing thin-wall packaging.
26 FILM & SHEET EXTRUSION | November 2022
Thermoforming processes use low melt-flow PP. “Crystallisation conditions
differ from those in injection moulding because the extruded sheet is cooled while being stretched,” he said. In a test, an Amfine clarifier
(CA1) – an organophosphorus salt-based product – was used to make thermoformed cups. The sheet used was 1.3mm
thick. In a performance compari- son with a cyclo-aliphatic carboxylate-type clarifier (CA2), it improved transparency at loadings of 500ppm. CA1 also showed an improvement in mechani-
cal properties, he said.
GHG reduction Neste and Illig presented a joint paper on how renewably produced PP can cut GHG emissions. Martin Bussmann, renewable polymers and chem-
icals at Neste Germany, detailed how the company has developed a PP grade based on renewable materials. The material is bio-based, but not biode- gradable – as it is identical to conventional PP. The material, called Circulen C14 HP 640, has been used to create extruded sheet for thermoform- ing – and was compared to a conventional grade. “For sheet extrusion, it is a drop-in solution,” he
said. “Identical processing parameters can be used.” A comparison of the two grades showed
near-identical shrinkage, stacking height, top load and wall thickness, he said. “The final technical evaluation showed no significant detectable differences,” he said. n The next Thin Wall Packaging conference is held in Cologne, Germany on 6-7 December 2022. For more details, contact Agata Swietek on +44 (0) 117 314 8111 (
agata.swietek@amiplastics.com).
CLICK ON THE LINKS FOR MORE INFORMATION: �
www.kuhne-ab.de �
www.harpak-ulma.com �
www.plexiglas.de �
www.ami.international �
www.cmtmaterials.com �
https://icpg.co �
www.promix-solutions.com �
www.basf.com �
www.amfine.com �
www.neste.com �
www.illig.de
www.filmandsheet.com
IMAGE: ICPG
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