MaProDe_Ox (2014)

During thermoforming, plastic sheets are heated and subsequently deformed through the application of mechanical stretching and/or pressure. This process directly impacts sheet properties such as material thickness in walls, corners, and bottom, crystallinity in the constituent layers, and particularly the oxygen gas permeability.

The aim of this study was to quantify the impact of thermoforming on thickness and oxygen transmission rate (OTR) of selected packaging materials (polypropylene (PP); PP/ethylene-vinyl alcohol co-polymer/PP (PP/EVOH/PP); polystyrene/EVOH/polyethylene (PS/EVOH/PE); amorphous polyethylene terephtalate/PE (APET/PE); APET/PE/EVOH/PE; polyamide/PE (PA/PE); and (PE/)PA/EVOH/PA/PE).

These materials were extruded in two different thicknesses and thermoformed into trays with the same top dimensions and variable depths of 25, 50, and/or 75 mm and a 50 mm tray with a variable radius of the corners. The distribution of the material thickness in the trays was visualized, showing the locations that were most affected by the deep drawn process.

The OTR results indicate that the calculated OTR, based on a homogeneous material distribution, can be used as a rough approximation of the measured OTR. However, detailed analysis of crystallization and unequal thinning, which is also related to the tray design, remains necessary to explain the deviation of the measured OTR as compared to the predicted one.

The MaProDe_Ox project “Impact of Material, Process & Design on the Oxygen Permeability of Thermoformed Packaging” was supported by grants from Flanders’ Food. We thank all participating companies from the Belgian packaging and food industry and Pack4FOOD for their contribution and constructive cooperation.

Evaluation of the Thickness and Oxygen Transmission Rate before and after Thermoforming Mono- and Multi-layer Sheets into Trays with Variable Depth. Buntinx M, Willems G, Knockaert G, Adons D, Yperman J, Carleer R and Peeters R. In: Polymers 2014, 6(12), 3019-3043.

Contact : mieke.buntinx@uhasselt.be

MaProDe_Ox tool

More information:

• Evaluation of oxygen transmission rate and thickness before and after thermoforming mono- and multilayer sheets into trays with variable depth. Buntinx M, Willems G, Adons D, Yperman J, Carleer R and Peeters R. In: Proceedings of the 26th IAPRI Symposium on Packaging 2013, pp. 386–398. Orally presented by M Buntinx, Espoo, Finland, 10–13 June 2013.

• Thermovormen wijzigt gasbarrière. Zuurstofbarrière kunststof verpakking verandert. Buntinx M, Willems G, Adons D, Yperman J, Carleer R and Peeters R. In: VMT 2013, 24, p. 39-41.

• Impact of thermoforming on the oxygen transmission rate and thickness of thermoformed trays. Buntinx M et. al. In: Proceedings of International conference on market trends and developments in plastics tubs, cups and tray packaging. Orally presented by M. Buntinx at Thin Wall Packaging, Cologne, Germany, 3–5 Dec 2013.

• New research gives further insights on O2-ingress in food packaging. Ragaert P, Vermeulen A, Buntinx M and Peeters R. In: New food 2014, 17, 8–11.

• Follow-up IWT TETRA project: Optimization of gas permeability of thermoformed packaging through improved insight in material, process and design [OptiThe_Ox2], 2013-2015.

• Impact van thermovormen op de gasbarrière van verpakkingen. Nieuwsbrief PACK4FOOD 28 feb 2014

• Evaluation of the Thickness and Oxygen Transmission Rate before and after Thermoforming Mono- and Multi-layer Sheets into Trays with Variable Depth. Buntinx M, Willems G, Knockaert G, Adons D, Yperman J, Carleer R and Peeters R. In: Polymers 2014, 6(12), 3019-3043.