With Leading Technologies to Real Recycling

Avoidance of plastic materials, waste reduction and recycling are becoming increasingly important. In contrast, the consumption of plastic products is constantly increasing due to a change in consumer behaviour. Manufacturers are faced with constantly growing challenges in this area.

On the one hand the product design has to be changed in such a way that recycling or second-hand use of the product is guaranteed, on the other hand the proportion of recycled materials in the product should be increased. Production processes that were previously designed only for the processing of virgin material and thus achieved consistently high quality under known conditions, are now severely disturbed or interrupted by contamination and strongly fluctuating material qualities at a higher recycling rate. Special requirements or the use in direct contact with food can no longer be realised with the existing production lines.

For the processing of recycled materials, however, an investment in new production lines is not absolutely necessary – Gneuss is an expert in plastics recycling and offers innovative technologies and system solutions for a plant “retrofit”. By replacing individual key components within the extrusion line, decisive key elements are supplied which make the existing line fit for the recycling cycle.

Our key elements for Real Recycling


The patented Rotary Filtration Systems and screen changers enable fully automatic, process and pressure constant filtration.


Gneuss’ MRS Extrusion System offers new possibilities in the venting or devolatilization of polymer melts.


The JUMP reactor reprocesses industrial and post-consumer PET waste to high value products.

Quality Control

The online viscometer enables precise measurement and control of polymer properties.

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Key Component Filtration System

An essential key element in the extrusion process is the cleaning of the plastic melt from various types of contaminated particles by means of melt filtration systems. In processes with relatively clean material, cleaning is carried out with the aid of simple screen changers that operate discontinuously or quasi-continuously. Due to the high purity of the input material, a change of the contaminated screens and a resulting process disturbance takes place rarely and at regular intervals.

The filtration process is decisively different if a high proportion of virgin material is exchanged by recycled material. The screens of the conventional filtration system become contaminated at shorter intervals, and as screen contamination increases, the pressure upstream of the filter rises, which can result in temperature and viscosity fluctuations. When changing screens, major process fluctuations can then occur and degraded and cracked particles can enter the melt flow. In contrast to this, Gneuss Filtration Systems work in a process and pressure constant way, so that, independent of the screen change frequency, continuous production and consistently high melt quality can be guaranteed.

The choice of the correct filtration system can have a decisive, positive influence on the economic efficiency of production. Back-flushing systems are often used for heavily contaminated materials, such as in recycling. The melt losses caused by these systems vary, sometimes considerably, depending on the filtration system used. With conventional back-flush screen changers, where back-flushing is usually done by diverting the melt flow, larger quantities of melt can thus be lost quickly. The Gneuss Filtration System RSFgenius with integrated back-flushing system sets new standards in terms of back-flush efficiency, as the quantity of material consumed as well as the pressure used can be exactly adapted to the process. The Gneuss Rotary Filtration Systems with patented screen disc technology are ideally suited for the processing of recycled material, as they operate continuously, pressure-constant and fully automatically, and have maximum self-cleaning efficiency.

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Key Component Extruder

In addition to the mechanical removal of foreign particles by means of melt filtration systems, thermal cleaning by diffusion plays a second key role in the extrusion process. In vacuum degassing, low-molecular components such as monomers, oligomers, solvents, reaction and decomposition products in the plastic melt are removed at high temperature in evacuated zones of the degassing extruders used. Decisive for the efficiency of vacuum degassing of polymer melts is the size of the melt surface in contact with the vacuum and its constant renewal. Usually, twin-screw and multi-screw extruders are used for this purpose.

Post-consumer waste generally has to be washed before reuse and still contains a high amount of residual moisture after the first mechanical drying. In contrast to conventional extrusion processes, with Gneuss MRS Extruders, this residual moisture does not have to be removed by drying or the like before processing. The moisture is removed from the plastic during extrusion by a vacuum system. The water also serves as a carrier medium for the removal of chemical additives such as dyes, stabilizers, acetaldehyde scavengers, carrier oils, solvents and many more.

For the use of the 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 the MRS extruder 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 material such as post-consumer waste, industrial waste from fibre and film production made of PET as well as other different hygroscopic polymers (e.g. polyamide) and also for polyolefins and polystyrene.

The design of the MRS extruder’s multi-screw section increases the melt surface available for degassing many times compared to conventional extrusion systems available on the market and generally requires a simple vacuum of only 25-30 mbar. For particularly demanding applications, vacuum systems up to 1 mbar specially developed for the process are also available.  The high degassing capacity removes volatile impurities, oils and odours extremely effectively. Polymers with a moisture content of up to 2% can be processed directly into high-quality end products.

Our solutions

Key Component Quality Control

When PET recycled material is used, the plastic melt often shows significant fluctuations in viscosity, e.g. between different batches, but also within a batch. The reason for this can be the material properties, but also different moisture contents. In PET processing, a constant IV value is of decisive importance for a reliable manufacturing process. Variations in the input viscosity require a flexible adjustment of the material ratio or the additives or a corresponding adjustment of the process parameters in order to regulate the final viscosity of the melt. Reliable online viscosity measurement is therefore essential for recording and controlling the melt viscosity.

The Gneuss Online Viscometer takes over the recording and control of the melt viscosity during production and ensures constant material qualities and properties even with fluctuating input viscosities via a fully automatic vacuum control.

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Key Component Polyreactor

The Gneuss Polycondensation Reactor Jump is flanged directly to the extruder and, with its sophisticated process engineering concept, ensures a targeted viscosity build-up of the PET melt. The Jump represents a compact, economical and fast alternative to conventional SSP systems and allows the reuse of the recycled material also in terms of upcycling. The Gneuss JUMP can also be retrofitted to an existing line at any time.

Our solutions