ITENE achieves detergent packaging through decontamination processes of recycled polyolefins 

June 27th, 2024

ITENE

El ITENE technology center has developed advanced processes decontamination of recycled polyolefins, specifically recycled high-density polyethylene (HDPE), which has allowed it achieve detergent packaging through extrusion blowing them in different sizes. 

The research has been carried out between June 2023 and 2024 within the framework of the ReciPOL project, financed by the Valencian Institute of Business Competitiveness (IVACE+i), and has focused on obtaining high-quality recycled materials.  

The project manager at ITENE, Félix González, explained that "although the post-consumer plastic decontamination processes developed usually focus on polyethylene terephthalate (PET), the elimination of contaminants in polyolefins is more complex due to their greater internal migration and low thermal stability, which generates degradation products. “These difficulties are aggravated by recycling cycles that involve greater degradation and contact with other contaminants, which can limit their application in sectors with higher quality requirements,” the researcher stressed. 

Therefore, in this project, we have sought to obtain new decontamination technologies for recycled polyolefins to increase recycling rates and promote their use in applications with higher quality requirements. Specifically, the work has focused on the conditioning, pretreatment, decontamination and transformation of waste polyolefins that are currently destined for low-value applications. 

Analysis of contaminants and controlled contamination 

For this, an analysis of post-consumer polyolefin contaminants was carried out. This allowed us to select the most critical ones in order to see what challenges the project was facing. Furthermore, through this selection and the optimization of the controlled contamination process (challenge test) it was possible to measure the effectiveness of the pretreatment and decontamination processes that were developed in the following stages. 

Subsequently, work was done on the development of polyolefin conditioning and decontamination processes. Firstly, a pretreatment process was carried out, once optimized and synergistically aligned with subsequent decontamination processes, where three different technologies were tested: water vapor, ozone and supercritical CO2. Water vapor was selected as the technology that met both good effectiveness in removing contaminants and feasibility, both economically and technically, of scaling this process. It is true that supercritical CO2 had greater efficiency, but due to the conditions usually used of hyperbaric pressures and high temperatures that achieve this condition, water vapor technology was chosen. 

Afterwards, the evaluation of the selected technology and its pilot scaling were carried out in a water vapor decontamination equipment designed at ITENE to scale the process and serve as a prototype for its validation and bring it closer to an industrial scale.  

Likewise, they selected additives to improve processability and material properties recycled, for which different formulations were designed that allowed optimizing the decontamination of the polyolefins and the properties of the packaging. Thus, the formulations that presented the best results were validated by hollow body blown extrusion to subsequently obtain bottles. Furthermore, it was found that the fluidity of the materials obtained was adequate and that the tensile strength was similar to that of the virgin material, although they had greater rigidity. Finally, the most promising formulation was selected for industrial validation. 

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