HUN-REN-BME Research Group

Development of PET packaging with increased heat resistance through waste recovery

Project ID:
Supported by:
Hungarian National Research, Development and Innovation Office (NKFIH)
1 Marc 2022 - 28 February 2025
Contracted amount of funding:
224 568 270 HUF
Supervisor (BME):
Prof. Dr. Andrea Toldy

Participant researchers (BME):
Dr. Dániel Gere
Dr. Ákos Pomázi
Prof. Dr. Andrea Toldy
Consortium partners (BME):
PRO-FORM Ipari és Kereskedelmi Kft.

Project summary

The vast majority of PET packaging, currently available on the market, has an amorphous structure (APET) and therefore their heat resistance is limited. The coronavirus epidemic further increased the need for crystalline PET (CPET) packaging with resistance to high-temperature, which also allows the improvement of food safety and preparation of foods with increased gastronomic value by baking. However, such raw materials can only be obtained in original form at high prices. The aim of the project is to develop formulations that enable the production of PET packaging materials meeting the increased application requirements at a lower cost, with value-added waste recovery (in the light of structural features that provide properties for higher expectations). This way we can develop a new kind of thermoformed product able to be heated up in an oven with its ready meal content, that has high heat stability and contains significant amount of recycled material. This will be possible based on the new finding outlined in the consortium members’ joint patent application, which results in a significant improvement in the properties of low-quality waste by a reactive method and a well-controlled process. The technology improvement activity includes methodological development of real-time sensor-information (e.g. adaptation of machine vision), which also serves the wider development of digitization in the industry. Our further aim is to investigate how the recyclability of high-temperature CPET trays made by the process can be solved for conventional heat-resistant and highly heat-resistant products depending on the additives and technological characteristics used in recycling, thus ensuring that the developed products can be fully integrated into the circular economy model. Increased interest in heat-resistant packaging targeting more demanding consumption has sparked international competition for an expanded market, but this is hampered by the high price of CPET. Significant advantage can be achieved in profitability if an innovative process manages to meet the quality requirements at a lower price. However, such a method is not known excepting the applicant’s invention, which provides priority protection and thus profitability of the products made using it. The indirect target group of the business plan is the demanding young consumers in Western Europe, but there is a visible trend of increasing expectation in Central Europe too, primarily with regard to food safety, which the products to be developed can provide at an outstanding level. Our main competitors are the few plastics processing companies in Western Europe (e.g. Faerch A/S in Denmark and Versatile Packaging in Ireland), mostly in the Far East and the United States, which already produce high-temperature trays for heating and baking semi-finished foods, but these products are still made of expensive industrial materials and not from cost-effective secondary raw materials (requiring appropriate treatment and technological features). With an average income of HUF 132 m, the results of the project can be calculated on an annual basis, so the return on the project is ensured within 4 years. Both the proportion of secondary raw materials used in the production of high-temperature products and the high recyclability factor ensure the long-term sustainability of the project result, as the project idea itself comes from a patent-based recognition whose protection gives us a long-term technological and price advantage. Our potential customers will consist of our current partners, other new food production and packaging companies as direct users, and we see significant potential in global distribution companies providing complex packaging systems, even in Hungary (e.g. KREIS Pack and Bunzl). Main aims of the project: Developing crystalline PET (CPET) formulations: developing formulations of CPET packaging materials that meet high heat resistance and food safety requirements. Development of CPET trays: based on the new formulations, development of CPET trays with high heat resistance and containing secondary (recycled) raw materials, suitable for heating ready meals in the oven. Investigating recycling: investigating the potential for recycling high-temperature CPET trays for conventional heat-resistant and high-temperature products, depending on the additives and technological parameters used in the recycling process, to ensure that the products can be integrated into a circular economy model.

Project results

Section 1
1 Marc 2022 - 28 February 2025
We collected and analyzed the molecular and material structure, raw materials, additives (such as nucleating agents, chain extenders, tougheners), and production technologies of high-heat-resistant PET sheet products. Based on the literature research, we selected property-enhancing additives (nucleating agents, chain extenders, tougheners), different PET types (including recycled materials), and extensively characterized them using analytical methods (e.g., DSC, TGA, Raman spectroscopy, etc.) Simultaneously, we conducted a detailed analysis of the structure, additives, and properties of commercial CPET products. We designed a temperable tool for the vacuum forming machine, with which we shaped various PET sheets under different settings. The results were compared with competitor data, and new formulations and production technology settings were proposed. We investigated the rigidity of highly crystalline CPET products through various approaches, such as precise control of crystalline content and the application of new nucleating agents. During the formulation development, we monitored changes in the morphology and crystalline structure of PET sheets toughened with a reactive elastomer and developed a new model for improving heat resistance and impact strength. We produced PET sheets foamed with supercritical carbon dioxide, characterized by a high crystalline content (CRF > 25%) due to molecular orientation during cell growth. We explored the effects of manufacturing technologies and parameters on the cell structure, thermal, and mechanical properties of foamed PET sheets. These low-density microcellular PET foams have the potential to significantly reduce material consumption and offer good thermal insulation properties, potentially serving as the basis for new recyclable packaging products, replacing foamed polystyrene. We published five scientific papers in English, and we presented our results at international conferences.
Storage modulus as the function of annealing time

Project-related publications

  1. Lukács N., Ronkay F., Molnár B., Marosfői B., Bocz K.: Characterisation of flame retarded recycled PET foams produced by batch foaming. Polymer Testing, 124, 108104/1-108104/9 (2023) 10.1016/j.polymertesting.2023.108104 IF=5.1 D1
  2. Bocz K., Ronkay F. Gy., Vadas D., Molnár B., Gere D., Czigány T., Marosi Gy.: Flame retardancy of PET foams manufactured from bottle waste. Journal of Thermal Analysis and Calorimetry, 148, 217-228 (2023) 10.1007/s10973-022-11423-3 IF=4.4 Q1
  3. Slezák E., Ronkay F., Bocz K.: Development of an engineering material with increased impact strength and heat resistance from recycled PET. Journal of Polymers and the Environment, 31, 5296-5308 (2023) 10.1007/s10924-023-02945-4 IF=5.3 Q1
  4. Lukács N., Decsov K. E., Molnár B., Ronkay F., Bocz K.: Increased processing temperature assisted reactive toughening of poly(lactic acid). Express Polymer Letters, 17, 169-180 (2023) 10.3144/expresspolymlett.2023.12 IF=3.3 Q2
  5. Slezák E., Ronkay F., Bocz K.: Improvement of mechanical properties of recycled PET by reactive toughening and post-crystallization. Acta Technica Jaurinensis, 15, 193-198 (2022) 10.14513/actatechjaur.00680
  6. Ronkay F., Molnár B., Szabó E., Marosi Gy., Bocz K.: Water boosts reactive toughening of PET. Polymer Degradation and Stability, 203, 110052/1-110052/9 (2022) 10.1016/j.polymdegradstab.2022.110052 IF=5.9 D1

© 2014 BME Department of Polymer Engineering - Created by: Dr. Romhány Gábor