If a circular economy is to be achieved, it will be necessary to recycle post-consumer thermoformed PET trays into PET trays. Currently, extensive use is made of post-consumer PET bottle flakes that are used in the manufacture of PET trays, but this raw material supply will continue to decline. As part of the circular economy, PET bottle flakes are increasingly being recycled into new bottles.

Recycling of post-consumer PET tray shredding to new PET tray sheet presents challenges to the recycling process:

• Unlike PET bottle flakes, the intrinsic viscosity of the crush of PET trays is too low to allow direct recycling on a conventional sheet extrusion line.
• The origin of post-consumer PET trays is not as controlled as with PET bottle flakes and there is a wide range of different types of trays in circulation, so the quality and property of the shred varies considerably.
• It is inevitable that the crushed tray will be cross-contaminated with other polymers, as it is difficult to completely exclude other polymers, especially due to coextruded or laminated layers.
• For food contact applications, efficient polymer decontamination (eg EFSA, FDA, SENASA, INVIMA) for monolayer structures is extremely important.
• The material should be purified efficiently, but at the same time, the processing should be as smooth as possible if the material needs to be processed in a continuous closed loop to ensure product quality.

With the new MRSjump extruder, Gneuss offers an extremely efficient system with which it is possible to process post-consumer PET shreds from thermoformed trays directly to the sheet to thermoform trays in a single step:

• No need for heat pretreatment of crushed PET
• Without the need to make pellets first and then feed the pellets into the sheet extruder
• With EFSA and FDA food contact certification

For this demanding tray-to-tray recycling process, Gneuss has developed the innovative MRSjump extruder that combines the high decontamination performance of the MRS degassing extruder, which has been well established over the past decades, with increased viscosity:

• The MRSjump extrusion process does not require any pre or post treatment of the input material, such as crystallization or pre-drying of the recycled material or a viscosity boost in a solid state polycondensation (SSP).
• The high degassing efficiency of the MRSjump extruder makes it possible to meet EFSA and FDA limits without time-consuming and costly upstream or downstream material treatment.
• The simple setup of the direct MRSjump extrusion process avoids the combination of different material treatments before or after extrusion and the resulting interface problems.
• Thanks to the short process chain, the melt remains within a defined and narrow residence time spectrum. Thermal and mechanical stress on the material is kept low. This results in excellent mechanical and optical properties to the container.
• The compact design of the MRSjump extrusion system means that it takes up little space and, compared to other concepts available on the market, it can easily be adapted to an existing sheet line with the same replacement requirements as an existing conventional extruder.
• The MRSjump extruder can process a wide range of input materials, from crushing monolayer and multilayer trays to combinations of materials that would be glued in a conventional heat pretreatment process (e.g. crushing PET / PE sheet, GAG, certain copolymers).
• In combination with Gneuss rotary filtration technology, a high purity of the melt is guaranteed.
• Quality assurance is also provided by optional systems for measuring melt viscosity and optical properties (measurement of color and transparency).