Packaging Collation shrink film is a demanding packaging application – for virgin polymers and all the more so for recycled materials. It needs to have a specific toughness, holding force, and shrink performance for it to guarantee package integrity as well as the necessary stability for storage and transport. Process parameters should remain constant when switching from virgin to recycled feedstock. Beyond this, as the film may be used as secondary packaging for bundling several products, making it the first thing the consumer sees, optics need to be of a highenough quality. During the projects that focused on multi-layer collation shrink films, ambitious substitution rates for virgin feedstock, ranging from 30% to 100%, were tested. The 30%-55% scenarios produced impressive results: the shrink film was nearly indistinguishable from that made of virgin material. Substituting virgin plastics for these amounts of secondary raw materials would already allow for a decisive reduction in emissions. Newcycling LDPE recyclates produce nearly 50% fewer emissions than virgin LDPE types. APK says its Newcycling dissolution recycling process can easily separate different polymers in multilayer plastic packaging – up to now, deemed non-recyclable – and transforms the target polymer into re-granulates with close to virgin properties. Dissolution recycling is an advanced physical recycling technology. Building on a mechanical pre-treatment step, it adds a solvent-based process step, during which the target polymer is separated and purification of contaminants, such as various additives or organic residues, also takes place. APK’s recycled LDPE, used during the shrink film tests, is marketed under the Mersalen brand. It is derived from complex PE/PA multilayer film waste. Increasing recycling quotas, potential mandatory use of recycled plastics in products across the EU market and a recently published Chemicals Strategy for Sustainability pushing strongly for a toxic-free environment: the European Commission has piled up a number of demanding challenges to the plastics and packaging value chains. However, bridging the gap between increased use of recycled plastics and attainment of the performance required for specific packaging applications can be facilitated by driving innovation in both design and technology. APK’s Newcycling process generates plastic recyclates of close to virgin quality, which are suitable to be used in cosmetic packaging.
PET tray-to-tray recycling in one step If a circular economy is to be realised, it will be necessary to consistently recycle post-consumer thermoformed PET trays back into PET trays. Currently, extensive use is made of rPET from bottles in the manufacture of PET trays but this supply of feedstock will continue to decrease. As part of the circular economy, PET bottle flake is increasingly recycled into new bottles. The recycling of regrind from post-consumer PET trays to new sheet for PET trays presents challenges for the recycling process, such as the intrinsic viscosity of the regrind from PET trays is too low to permit direct recycling on a conventional sheet extrusion line. It is also unavoidable that tray regrind will be cross-contaminated with other polymers, as it is difficult to completely exclude other polymers, especially due to co-extruded or laminated layers. Thus, for this demanding process of tray-to-tray recycling, machine maker Gneuss has developed the MRSjump extruder, which combines the decontamination performance of the MRS degassing extruder with a viscosity boost. Furthermore, Gneuss says the extrusion process does not necessitate any pre or post-treatment of the input material, such as crystallisation or pre-drying of the recycled material or an IV boost in a solid state polycondensation (SSP). It also adds that the high degassing efficiency of the extruder makes it possible to comply with EFSA and FDA limits without time and cost-intensive upstream or downstream material treatment. Other benefits are the simple set-up, compact design and the ability to process a wide range of materials, from regrind from mono and multi-layer trays to material combinations that would stick together in a conventional thermal pre-treatment process (e.g. sheet regrind from PET/PE, GAG, certain copolymers). Thanks also to the short process chain, the melt remains within a narrow, defined residence time spectrum. The thermal and mechanical stress on the material is kept low, allowing for mechanical and optical sheet properties. Thus, recycling and decontamination are for the first time made possible with the MRSjump Extruder, within one single extrusion step, without upstream or downstream material treatment steps. This opens up new possibilities for the recycling of tray regrind.
Gneuss has introduced its MRSjump recycling extruder, a one-step extrusion process for PET tray-to-tray recycling
NOVEMBER / DECEMBER 2020
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