Currently, dairy packaging waste made of high impact polystyrene (PS) is not recycled to produce new containers for the same product, because this material has a particular chemical composition that causes its strong deterioration with recycling, hindering its performance for producing new resistant and safe containers for safe food preservation.
PS is a hard-to-replace petrochemical polymer due to its low cost, light weight and impact resistance which prevents container breakage.
Other unique properties include the cutting ease when separating a single serving cup of yogurt from the 4-pack.
That was until now, as Usach's Laben Chile researchers, Dr. María José Galotto and Dr. Eliezer Velásquez, developed a mono-material polystyrene container, incorporating a high proportion of post-consumer recycled polystyrene with a functional barrier. This process ensures the safety of the new materials developed using recycled material, thus meeting the properties required for the industrial production of new packaging.
This is the Fondef IDeA project “Application of the circular economy model for the dairy industry entitled “Developing food packaging from post-consumer recycled polystyrene,” funded by the National Agency for Research and Development (ANID), Universidad de Santiago de Chile, Centro de Innovación para Envases y Embalajes, and Co-Inventa.
The initiative was supported by the strategic collaboration of the companies Ecovia (Reciclajes ConoSur), COEXPAN-Chile, Soprole, Watt's and Colun.
Head of the study Dr. María José Galotto, notes that “what is most important about the project is to be able to demonstrate that we are in a position to apply the circular economy in the area of food packaging, especially in the case of polystyrene, which is the material widely used for yogurt containers.”
She goes on to note that it is important to emphasize that this initiative has been carried out hand in hand with the industry, “with the entire value chain, from recyclers, processors and users, demonstrating that this material is recyclable, that it does not affect the characteristics of the packaged product (yogurt) and above all guarantees its safety.
This innovation has benefited from the participation of value-adding company Ecovia, Coexpan-Chile—the company that transformed the new material, and the direct participation of the dairy companies Soprole and Watt's dairy. which have confirmed the good performance of the new material.
This technology has been proven in yogurt packaging using conventional industry equipment, requiring no modifications to the production lines.
Results of industrial tests using post-industrial recycled polystyrene have been very attractive and confirm that the yogurt retains its sensory and safety characteristics.
Dr. Eliezer Velásquez said that the first step was to study the effect of repetitive recycling of polystyrene from yogurt containers collected at pilot clean points in Chile, to identify the need for improvements and alternative solutions.
“The scientific results of this study were very insightful and confirmed the imperative need to develop alternative technologies to enable polystyrene recirculation and the manufacturing of new food packaging from these wastes.”
The researcher also points out that “the formulation developed based on recycled polystyrene increases the impact resistance and ductility of the plastic, up to the same values as virgin polystyrene, through its additive version without affecting its recyclability.
The amount of post-industrial recycled polystyrene incorporated into new articles would advance compliance with the goals of the REP Law,” Dr. Velásquez emphasizes.
The director of Laben Chile, Dr. Abel Guarda, said that, as the country's leading center in containers and packaging, “we are generating specific results concerning the real problems of containers and packaging, preventing them from becoming waste after they have completed their mission as containers.
Our goal is to protect the environment and Laben Chile's actions in this regard contribute to provide knowledge and information to companies on how to work with these materials so that they do not become waste.”
Science - Business Partnership
The project involved the participation of a team of professionals from different disciplines and market leaders in recycling, production of polystyrene containers, and the food industry that uses these containers.
Post-consumer and post-industrial recycled polystyrene were separated, recycled and washed at Ecovia (Reciclajes ConoSur).
Pilot tests of the prototype were carried out at the Packaging Innovation Center (Laben Chile).
Coexpan supplied the virgin polystyrene and scaled up the prototype sheet and packaging developed by the researchers in an industrial plant, from post-industrial recycled polystyrene, confirming the machinability of the developed structure.
The project was also supported by Soprole, Watt's, and Colun as food industry partners.
Industrial trials of yogurt packaging have already been carried out at Soprole and Watt's.