MATERIAL IN DETAIL
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attempt to completely remove this and heavily rely on the air elutriation step for this, with a delicate tradeoff between the resulting quantity and quality of their rPET product. It not uncommon that this results in this recycled PET which is only suitable for different, lower value outlets such as strapping, which is the opposite of the desired, high value bottle-to-bottle rPET stream. Thus, in a circular economy model it is not only the material that comes back into the loop, but also the challenges too: producers that are introducing poorly recyclable packaging items will also face the problem of good quality rPET scarcity when, to comply with their sustainability promises and obligations, they will need to use PCR materials from the very same pool that they are contaminating. Hence, rapid innovation in this area is key, and an opportunity for the entire packaging value chain is represented by polyethylene furandicarboxylate (PEF) with its excellent barrier performance and compatibility with PET. PEF, an innovation that fits the drive towards circularity PEF is a performance polyester that is made from 100% renewable resources. Thanks to its outstanding gas barrier, coupledwithbalancedthermomechanical and processability properties, it has an excellent fit in packaging applications. Additionally, PEF is compatible with PET mechanical recycling assets, and when it is processed as part of the PET recycling stream it has been proven that PEF has lower impact than other barrier materials on haze and other properties of the resulting rPET products. /1/, /2/ Avantium Renewable Polymers, a 100% subsidiary of Avantium, plans to build the first commercial-scale plant for the production of FDCA (furandicarboxylic acid), a monomer for PEF and other
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Fig 1: OTR data and Barrier improvement factors of 500 mL flat base, 19,7 g bottles, courtesy of Logoplaste Innovation Lab. The OTR is measured with the sensor dots method.
high performance polyesters. This first- of-a-kind plant, which Avantium aims to have on-stream during 2023, will be built in Delfzijl, the Netherlands and will produce 5 metric kilotons of FDCA and PEF per year. Avantium has already proven its technology to produce these novel materials at smaller scale from its pilot plant in Geleen, the Netherlands, and is using the FDCA and PEF produced here to develop and accelerate the market introduction of various high- value applications. Key amongst these pioneering uses of the novel polymer is its application as a barrier material in multilayer PET bottles, where PEF represents a valid alternative to the current barrier materials used today 2 , combining enhanced shelf life performance with vastly improved sustainability. All-polyester multilayer bottles with the right barrier performance In a previous article published in ComPETence Two:20 /2/, multilayer PET bottles utilizing PEF as a barrier layer
were shown for the first time. These bottles were produced using standard PET bottle processes and geometries, and resulted in similar material distribution and mechanical performance as a monolayer PET reference, with no appreciable color or haze differences when compared to monolayer PET. When it comes to thebarrier performance of the multilayer bottle, OTR data were presented which showed that the shelf life of a product can be extended by 80% when a 10 wt% PEF layer is used compared with a monolayer PET bottle of the same weight and design. In this further communication, the CO 2 retention of the PET/PEF multilayer bottles will be detailed, including a comparison with incumbent solutions from the market where Polyamide is used as a barrier layer. Figure 2 shows the loss of carbonation from these bottles with time - as expected, after an initial drop in carbonation during the first two weeks, the trend stabilizes. The CO 2 transmission rate depends on the permeability of the bottle walls to CO 2 and the carbonation
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