According to Gneuss an investment in new production facilities is not absolutely necessary for the processing of recycled materials. The company offers technologies and system solutions for retrofitting. With the replacement of individual key components within the extrusion line, decisive key elements are supplied which make the existing line fit for the recycling cycle. The focus here is on cleaning the plastic melts. Gneuss offers Rotary Melt Filtration Systems for an efficient and economic filtration of plastic melts as well as MRS Extruders for degassing and decontamination of plastic melts for direct food contact.
Filtration of highly-contaminated recycled materials
The Gneuss Rotary Filtration Systems with patented filter disc technology are suited for the processing of recycled material, as they operate continuously, with constant pressure and fully automatically. Due to the annular screen arrangement a screen change takes place without disturbances or interruptions of the production process. Depending on the filter fineness, the screens can be reused up to 400 times, which can mean a fully automatic filtration process without the need for several weeks of personnel. Constant production process even with finer filtration is stated to achieve high end product quality. Screen cleaning of the RSFgenius Filtration System by means of an integrated backflush piston system is being autmated, where a small amount of filtered melt is regularly shot through the dirty screen.
By using the right filtration system, such as the pressure-constant and process-constant RSFgenius Filtration System with back-flushing technology, the quality and productivity restrictions to be expected from a high use of recycled material can be considerably minimised.
Direct use of PCR for plastic packaging
When post-consumer and industrial waste is processed, the recycled plastics from previous use contain chemical additives such as dyes, stabilisers, acetaldehyde scavengers, carrier oils, solvents and more. For the use of recycled material in contact with food or skin, the purity requirements set by food authorities such as FDA, EFSA or other local authorities apply. All organic and inorganic potential toxins must be removed, which is achieved with a high decontamination performance during the degassing phase.
For more than a decade, the Gneuss MRS Extruder has been used for the recycling of highly contaminated recycled materials such as post-consumer waste, polyester industrial waste from fibre and film production as well as polystyrene, nylon and other hydrophilic polymers.
- The MRS Extruder is based on a conventional single-screw extruder combined with a multiple screw section in the degassing zone:
- the melt surface area available for degassing is increased many times over thanks to the multi-screw element with eight individual satellite screws rotating against the extruder barrel
- vacuum degassing with a simple vacuum of 25-30 mbar
- effective removal of volatile impurities, oils and odours
- processing of polymers with a moisture content of up to 1%
- effective decontamination of 100% post-consumer recycled products and 100% bottle flakes for use in food contact with, among others, the LNO of the FDA, the EFSA approval or several local approvals.
The MRS recycling technology is modular and can be integrated into existing production lines. By replacing individual components or integrating the complete Gneuss processing unit, based on a Rotary Filtration System, an MRS Extruder with vacuum system and control technology, existing production processes can be made fit for the recycling cycle.
System solutions for recycling of packaging waste
Gneuss offers turn-key lines for the production of thermoforming sheet from recycled material as well as for the pelletising of all types of plastic waste.
- One area in which MRS extrusion technology is particularly successful is PET sheet extrusion. More than 30 tailor-made Gneuss sheet lines have been installed worldwide in recent years. The lines process both, virgin and recycled material and are also used for packaging articles with food contact:
- economically process without pre-drying and crystallisation
- flexible processing of a wide variety of materials such as virgin material, post-consumer bottle flakes and mixtures such as PET and PE or PET and PETG
- many years of experience in processing into a wide variety of packaging products such as transparent film packaging for food and non-food articles, blister packaging, thermoformed trays and trays for food
- flexible conversion to foam film production by means of physical foaming with a density reduction of over 50%.